landscapeforlife.org

LANDSCAPE FOR LIFE
TM
WORKBOOK
How to harness nature’s power to create
a healthy, beautiful home garden
a c k n ow le d gements
Landscape For Life is a project of the United States
Botanic Garden and the Lady Bird Johnson Wildflower
Center at The University of Texas at Austin.
Landscape For Life is based on the principles of SITES,
The Sustainable Sites Initiative , the nation’s first rating
system for sustainable landscapes (www.sustainablesites.
org), an interdisciplinary effort by the American Society of
Landscape Architects, the Lady Bird Johnson Wildflower
Center at The University of Texas at Austin, and the
United States Botanic Garden in conjunction with a
diverse group of stakeholder organizations. SITES offers
technical tools for professionals who design, construct,
operate, and maintain landscapes of all sizes. Landscape
For Life presents this information in an easy-to-use form
for homeowners and gardeners.
TM
The information in this workbook is also available on the
Landscape For Life website (www.landscapeforlife.org).
Written by Janet Marinelli
Designed by Elizabeth Ennis
A sustainable garden in Texas
includes a buffalograss lawn and
other native plants that nurture
wildlife.
Illustrations pages 16, 17, 22, 24, 44, 63, 66, 73, 76, Elizabeth Ennis; pages 2, 4, 5, 42, Sustainable Sites
Initiative
Map page 58, Sustainable Sites Initiative, page 79 top and bottom, public domain images via Wikipedia
Cover photos, left to right: first two images, Bigstock.com, H. Zell, last two images, Bigstock.com. Photo
page i, Andy and Sally Wasowski, Lady Bird Johnson Wildflower Center; page ii, Steve Greer/VIREO;
page 1, Andy and Sally Wasowski, Lady Bird Johnson Wildflower Center; page 3, public domain image
via Wikipedia; page 7, Andy and Sally Wasowski, Lady Bird Johnson Wildflower Center; page 11, public
domain image via Wikipedia; page 14, Bigstock.com; page 20, Lynn Betts; pages 21 left and right and
26, public domain images via Wikipedia; page 32, public domain image via Wikipedia; page 35, Manuel
Broussard/FEMA; page 36, Ward Wilson; page 39, public domain images via Wikipedia; pages 41 and 43,
Nancy Arazan; page 45 left and right, Walter Siegmund; page 49, Holly Shimizu; pages 50 and 52, public
domain images via Wikipedia; page 55, public domain image via Wikipedia; page 56, H. Zell; page 57,
public domain image of Garden in the Woods via Wikipedia; page 58, public domain image via Wikipedia;
page 61, Shaw Nature Reserve; page 64, Bigstock.com; pages 69 and 71, Andy and Sally Wasowski, Lady
Bird Johnson Wildflower Center; page 70, public domain image via Wikipedia; page 75, public domain
image via Wikipedia; page 77, Iowa State University Extension; page 81, Joe Mabel; page 83, Andy and
Sally Wasowski, Lady Bird Johnson Wildflower Center; page 87, public domain images via Wikipedia; page
84, public domain image via Wikipedia; page 90, Russell Lee; page 91, Sustainable Sites Initiative; page
92, public domain image via Wikipedia; page 95, Bigstock.com; pages 96 and 97, public domain images
via Wikipedia; page 99, Biswarup Ganguly; page 100 top, Bohringer Friedrich and bottom, public domain
image via Wikipedia; page 103, Bigstock.com
i
I n t rod uc tion
w o r ki ng w ith nature to create a
h e a lt hy, be autiful home l andsca pe
Landscape For Life shows you how to work with nature
for a beautiful, sustainable garden, no matter where you
live, whether you garden on a city or suburban lot, a 20acre farm, or the common area of your condominium.
Conventional gardens unintentionally often work against
nature. They can damage the environment’s ability to
clean air and water, reduce flooding, combat climate
change, and provide all the other natural benefits that
support life on earth—including us.
The good news is that even one home garden can begin
to repair the tattered web of life. It’s possible to create a
great-looking garden that’s healthier for you, your family,
your pets, and the environment—and that saves you time
and money.
The Landscape For Life workbook helps you transform
your home garden into a beautiful and healthy refuge
for you and your family. After an introductory chapter on
the many natural benefits that landscapes provide, the workbook is divided into six sections: Getting
Started, Soil, Water, Plants, Materials, and Human Health. Each chapter includes helpful advice on
gardening practices that take advantage of natural processes at work on your property.
ii
C o n t ents
Landscapes Give Back . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
The carbon cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
The water cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
The nitrogen cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Understanding your site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Checklist for choosing a new home site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Checklist for garden construction and renovation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
What to ask when hiring a landscape designer or contractor . . . . . . . . . . . . . . . . . . . . 13
Soil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Get to know your soil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Slow food for healthy soil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Fertilizer tips for a sustainable garden . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Compost: homemade humus for healthy soil . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Organic mulches and how to apply them . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Green manures and how to use them . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Dealing with “problem soils” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Sandy soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Clay soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Wet soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Acid soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Alkaline soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Compacted soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Shallow soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Saline soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Contaminated soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Sustainable potting mixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Gardening in raised beds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
iii
Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Create a water-thrifty landscape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Select plants adapted to local precipitation patterns . . . . . . . . . . . . . . . . . . . . . . 37
Use alternatives to drinking water for irrigation . . . . . . . . . . . . . . . . . . . . . . . . . . 37
A guide to water-thrifty irrigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Smart strategies for managing stormwater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Create a rain garden . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Limit impervious surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
A guide to green roofs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Protect and restore vegetative buffers along waterways and wetlands . . . . . . . . . . 48
Sustainable water features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Identify and remove invasive species on your property . . . . . . . . . . . . . . . . . . . . . . . . . 51
Grow plants adapted to the conditions in your garden . . . . . . . . . . . . . . . . . . . . . . . . . 53
Grow native plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
What’s your ecoregion? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Landscape for wildlife . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Protect and restore your landscape’s vegetation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Green your lawn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Landscape to increase your home’s energy efficiency . . . . . . . . . . . . . . . . . . . . . . . . . 71
Creating summer shade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Blocking winter winds. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Reduce the urban heat island effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Reduce the amount of material necessary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Reuse existing and salvaged materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Avoid wood from threatened tree species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Choose certified wood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Purchase other certified products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Select local materials and products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
iv
Use concrete alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Select materials that do not pollute stormwater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Choose no- or low-VOC products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Human Health . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Grow a food garden . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Limit your exposure to pesticides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Organic gardening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Integrated pest management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Reduce light pollution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Create garden spaces that enhance health and well-being . . . . . . . . . . . . . . . . . . . . . 103
v
L a nd scape s Give Back
When we create sustainable landscapes, the landscapes give
back, providing natural benefits that are essential to daily life,
like cleaning the air and water, and maintaining soil fertility. We
have underestimated or even ignored their value when making
decisions that affect the land, but they are the key to creating
home gardens that meet our needs without compromising the
ability of our kids and grandkids to meet theirs. Among the many
natural benefits of sustainable landscapes are:
• Cleaner air and water
Plants, through photosynthesis, provide us with the oxygen we
breathe. Plants and organisms in the soil remove and break
down pollutants, including those that trigger asthma and other
illnesses.
ooler towns and cities
•C
Trees and other plants provide cooling shade and via the
carbon cycle (page 2) remove carbon dioxide, the major
greenhouse gas, from the atmosphere.
• Food, medicine, wood, and other products
Plants transform carbon dioxide into food, life-saving medicines,
wood, and countless other products.
One estimate is that every year
healthy landscapes provide $33
trillion worth of natural services,
including natural water storage
and flood control—nearly
twice the global gross national
product of $18 trillion.
• Wildlife habitat and biological diversity
Plants fuel the dazzling diversity of life on this planet, from the blue whale, which can weigh 150 tons, to the
Cuban bee hummingbird, which weighs one-seventeenth of an ounce.
• Pollination
Bees, birds, bats, and other animals pollinate crops.
• Natural water storage and flood control
Stormwater is absorbed by plants or slowly trickles through the soil and into underground reservoirs called aquifers,
preserving the land’s natural water cycle or hydrology (page 4).
• Waste decomposition and soil fertility
The nitrogen cycle (page 5) transforms wastes into the nutrients necessary for sustaining life.
• Erosion and sediment control
Vegetation helps maintain soil structure and fertility and prevents erosion and pollution.
• Human health and well-being
Our connection to nature sustains us physically and mentally.
1
T h e C a r b o n C y cle
Carbon is a fundamental building block of life on earth, and without it we could not survive. When we change how
it is distributed on the planet, it can cause serious problems. In fact, we already have altered global carbon cycles
through use of fossil fuels, farming methods, and land development practices. The good news is there are steps we
can take in our own landscapes to help reverse this trend.
What To Do
Restoring and maintaining your landscape’s biomass (page 66), which determines its ability to absorb carbon
dioxide, and strategically planting trees and shrubs to improve your home’s energy efficiency (page 71) are two of
the most important things you can do to help keep your town or city cool and stabilize the global climate.
Natural
air-sea
exchange
Natural
photosynthesis
and respiration
Human
emissions
taken up by
oceans
Oceans
Atmosphere
Human
emissions
taken up by
vegetation
excess from
human
emissions
Human
emissions
created by
land-use
changes
Human
emissions
created by
burning
fossil fuels
Vegetation
and Soils
Fossil
Fuels
The Carbon Cycle
Plants are the foundation of the biological carbon cycle. Through photosynthesis they use the
sun’s energy to convert carbon dioxide and water into complex carbohydrates, the building
blocks of the foods that all animals, including us, need to survive. Carbon is a major component
of plant and animal tissue, also known as their “biomass.” In the process of photosynthesis,
plants also produce oxygen, maintaining a livable atmosphere.
The cycle continues when plants and animals die and the carbon in their tissues becomes food
for decomposing microbes. These decomposers help maintain the soil’s organic matter, which is
essential for fertility.
Sometimes plant and animal remains are trapped in the earth or on the ocean floor, beyond the
2
reach of decomposers. Over hundreds of millions of years, they become fossil fuels. Fossil fuel
combustion in power plants, cars, lawnmowers, leaf blowers, and other devices releases carbon
dioxide into the atmosphere. It is now overflowing with the carbon that was once locked up in
ancient deposits of coal, oil, and natural gas.
We’ve also increased atmospheric CO2 levels by farming and clearing forests, releasing much of
the carbon they once stored. It’s estimated that the conversion of natural ecosystems to plowbased agriculture has depleted organic carbon in temperate climate soils by as much as 60
percent and in tropical soils by up to 75 percent. Excess CO2 in the atmosphere is the principal
cause of global warming.
3
T h e Water C y c le
The planet’s natural water cycle is disrupted when we damage soils and natural habitats. Replacing healthy,
permeable soil with asphalt and concrete and compacting soil with heavy machinery results in less water infiltrated
into the soil and more rainwater runoff. Stormwater runoff is one of the leading sources of water pollution in the U.S.
What To Do
See pages 41- 48 for tips on how to manage stormwater on your property, from planting a rain garden to
collecting rainwater for irrigation.
Precipitation
Condensation
Evaporation
Surface runoff
Surface runoff
Transpiration
Evaporation
Plant
uptake
Groundwater
flow
Infiltration into
groundwater
Aquifer
The Water Cycle
The water we use today has been around for hundreds of millions of years, and the amount probably
hasn’t changed very much. Water changes from gas to liquid to solid form, and is taken in by plants
and animals in a large, continuous cycle. It drives the world’s weather and climate, supports plant
growth, and makes life possible.
Five processes fuel the water cycle: condensation, precipitation, infiltration, runoff, and
evapotranspiration. The sun heats surface water and it evaporates as water vapor. The water vapor
condenses to form clouds and falls as precipitation. On a well-vegetated site with healthy soils,
rainwater infiltrates slowly into the ground, is taken up by plants, and returns to the atmosphere when
the plants transpire. Some is stored in aquifers, and may return to the surface as a spring or seep
into streams, rivers, lakes, and the ocean. In undeveloped ecosystems, only a small portion of rainfall
becomes runoff. Healthy soils allow rainwater to infiltrate, preventing erosion and flooding, and plants
slow the speed and intensity of runoff.
4
T h e Ni tr o g en C y c le
Nitrogen is a critical element for most life. When we alter the amount and types of nitrogen found in air and water,
it can lead to significant problems. For example, supplementing the soil’s nitrogen supply with synthetic or organic
nitrogen fertilizers increases air pollution, including greenhouse gases, and can pollute our waterways.
What To Do
Homeowners and gardeners can help reduce nitrogen pollution by mimicking nature’s way of maintaining soil
fertility in a forest, prairie, or other natural landscape—using compost and mulches instead of concentrated nitrogen
fertilizers, for example. See pages 21-27 for details.
Fossil Fuel
Emissions
Gaseous
Losses
N and N O
Atmospheric
Nitrogen N
2
2
2
Precipitation
Lightning
Fixation
Runoff
Fertilizers
Fertilizers
Denitrification
Organic Matter
R-NH
Fossil Fuels
Nitrogen
Uptake
2
Eutrophication
Denitrifying
Bacterias
Bacteria
Fixation
Nitrogen
Fixation
Decomposers
Nitrates NO
Mineralization
Ammonium
NH
3­-
Leaching
Nitrification
Nitrites NO
2
4+
Nitrification
The Nitrogen Cycle
Nitrogen is the nutrient needed in the largest amount by plants, and managing nitrogen in the
soil is a key part of a healthy and productive home landscape.
Nitrogen constantly cycles between the atmosphere and the soil. Almost 80 percent of the
5
earth’s atmosphere is comprised of elemental nitrogen, or N2, but living organisms cannot
use this form directly from the air. It must be “fixed” or converted by microorganisms into
ammonium and nitrates that plants can utilize. Some nitrogen-fixing bacteria live in the root
nodules of legumes such as peas and beans, alfalfa, and clover. The plants supply the bacteria
with energy and nutrients in return for nitrogen fixation. Growing these plants as cover crops
helps ensure a good level of nitrogen in the soil (page 27).
The nitrogen taken up by plants makes its way into organisms higher up the food chain. When
plants and animals die, decomposers convert some of the nitrogen back into ammonium,
available again for plant use.
Other microbes carry on denitrification, which converts the fixed nitrogen in the soil into
elemental nitrogen, nitric oxide, which contributes to smog, and nitrous oxide, a greenhouse gas
300 times more powerful than carbon dioxide. Supplementing the soil’s nitrogen supply with
synthetic or organic nitrogen fertilizers increases denitrification and produces these polluting
emissions. Soils enriched with nitrogen fertilizer emit two to ten times as much nitrous oxide as
unfertilized soils. Cultivating the soil with a rototiller or a spade also releases nitrous oxide, as
well as carbon dioxide and methane, another powerful heat-trapping gas.
Human activities have doubled the amount of fixed nitrogen entering the nitrogen cycle in just
100 years. These include the manufacture and use of nitrogen fertilizers, the combustion of
fossil fuels, forest burning, and livestock ranching, which causes large amounts of ammonia to
enter the soil. This increase in fixed nitrogen causes climate change, acid rain, the acidification
of soils and the loss of soil nutrients, and the acidification of streams and lakes in many regions.
When carried into local waterways along with excess phosphorus from fertilizers, it leads to
eutrophication or algal blooms that consume oxygen, killing fish and shellfish. In coastal waters,
such “dead zones” cause significant declines in fisheries. In freshwater lakes, excessive nitrogen
can be a serious health issue, especially in summer when warmer waters allow the growth of
blue-green algae, or cyanobacteria, which can cause diarrhea, vomiting, nausea, skin rashes,
and lesions in both humans and pets. Excess nitrates that leach into drinking water can also be
dangerous to human health.
6
G e t tin g Started
To harness nature’s power in your landscape you need to know
what natural processes are at work—what type of soil you have,
for example, how much precipitation you receive, and what plants
grow naturally in your area given these conditions.
In conventional landscapes, decisions are often made on
aesthetics alone. You want to re-create a picture of a lovely
garden. You may not know that you don’t have the soil or
climate required by the plants in the photo. So you work against
nature, altering the soil to suit the plants, fertilizing, and watering
constantly so they will survive. And they still don’t thrive, because
they’re not adapted to the conditions in your garden.
A sustainable garden can be just as beautiful as any other
landscape, and can provide a wealth of health and environmental
benefits. It can also save you money. This section of the
Landscape For Life workbook helps you lay the groundwork for
greening your garden by collecting essential information about the
natural forces at work there.
Lanceleaf coreopsis and other
native plants grow in a Texas
garden attuned to the natural
processes at work on the site.
How To Get Started
Use the Landscape For Life Site Assessment to collect information (page 8).
Consult the following checklists if you’re looking for a new home site, creating a new garden or
renovating an existing one, or hiring a landscape designer or contractor:
Checklist for choosing a new home site (page 10)
Checklist for garden renovation and new construction (page 12)
What to ask when you are hiring a landscape designer or contractor (page 13)
7
U n d e r s ta ndi ng Yo u r Sit e
This simple site assessment is divided into six major categories: Climate and Energy, Soil, Water, Plants, Materials,
and Human Health. When you’re finished you’ll have the information you need to choose which landscaping
strategies and gardening practices make sense for you. See pages iii-v for an index to all the sustainable strategies
and practices included in the Landscape for Life workbook.
Start by sketching a basic template of your property. Consulting a plat map or site survey can be helpful. Using
colored pencils on graph paper, draw your house and property to scale, allowing a quarter inch per foot. Locate
walks, driveways, other paved surfaces, the garage, and outbuildings. Also note where any underground utilities,
such as water, gas, and electric lines, enter the house.
CLIMATE AND ENERGY
• On one copy of your template, add climate-related information, such as areas of your home that are affected by
the sun and wind. See the section on landscaping for home energy efficiency on pages 71-78 for details.
SOIL
• On another copy of your template, note areas with relatively undisturbed native soil and vegetation that should
be protected, as well as problem areas where topsoil was removed or compacted, where it stays wet, or where it
is dry and exposed.
• Become familiar with the particulars of your soil, including its texture, structure, pH, and nutrient levels. See
pages 15-20 for more information.
• Consider having your soil professionally tested.
• Identify and note a well-drained spot on your property shaded from the hot afternoon sun where you can locate
a compost pile.
WATER
• On a fresh copy of your template, sketch in any wetlands, shorelines, creeks, streams, or other waterways on or
adjacent to your property.
• Mark where rainwater comes rushing off roofs or down gutters, where it flows down paved surfaces, and where
it pools during storms.
• Note impervious paved surfaces such as your driveway and pathways.
• Note the type and location of your irrigation system, if you have one.
PLANTS
• On another copy of your template, mark in red any invasive plants growing on your property. For tips on
identifying invasive species, see page 51.
• Identify your plant hardiness zone.
• Determine the average annual and monthly precipitation rates.
• Identify your ecoregion and its major native plant communities. You’ll find a map and descriptions of the major
ecoregions in the U.S. on page 60.
8
• Mark any native plants and plant communities. Note any large trees growing in your landscape, and circle the
areas they shade over the course of the day.
• Circle areas that receive sun all day long and note those that receive morning sun, midday sun, afternoon sun
only, or full shade.
MATERIALS
• Locate an area for convenient storage of recyclable materials.
• Use the Checklist For Garden Construction and Renovation on page 12 for materials tips if you are creating a
new garden or renovating an existing one.
HUMAN HEALTH
• Note shady, protected, or private areas for relaxation or socializing.
• Note open areas for outdoor games and physical exercise.
• Mark areas in full sun where it would be appropriate to grow herbs, vegetables, or fruits.
9
Checklist For Choosing A New Home Site
If you’re searching for a new home site, you can help preserve prime farmland, keep eroded soil and polluted
runoff out of local waterways, protect disappearing wetlands, and preserve critical habitat for imperiled plants and
wildlife. Careful site selection can also protect your home from future flooding and promote health by encouraging
you and your family to walk, bike, or use public transit instead of driving.
Don’ts
5 Don’t build on prime farmland.
Fact: Between 1982 and 1997, 18.5 million acres of prime and unique American farmland was lost to
development. Farmland loss is irreversible—the characteristics that make these soils superior for growing food and
other crops cannot be restored.
Don’t construct your house on a 100-year floodplain.
Fact: Flooding is the number one most common natural disaster in the United States. From 1994 to 2004, U.S.
flood losses averaged more than $2.4 billion a year.
Flood plains are not only dangerous, they perform essential ecological functions. They store floodwater and filter
out pollutants. They help recharge groundwater and provide habitat and migration corridors for plants and wildlife.
They can also offer open space for human recreation.
You can find local flood maps on the Federal Emergency Management Agency (FEMA) website (http://msc.fema.
gov/). Click on “Map Search,” then enter your complete address in the boxes provided, with street address, city,
state, and zip code if possible. When your address is located, click on “View.” You may need to use the “Zoom
in” button to find your location on the map. Flood zones are clearly marked. There is a tutorial on the wealth
of information on these flood maps, called Flood Insurance Rate Maps (FIRMS), here (www.fema.gov/library/
viewRecord.do?id=2324).
5 Don’t disturb soil or vegetation within 50 feet of a wetland.
Fact: Wetlands, including marshes, swamps, and bogs, are among the most productive and biologically diverse
ecosystems in the world. They provide habitat for fish and wildlife, natural water cleansing, floodwater storage,
protection against shoreline erosion, and opportunities for recreation. They’re also beautiful.
Don’t destroy critical habitat for imperiled plants and animals.
Fact: Currently, there are 1,216 animals, 716 flowering plants, and 26 ferns on the U.S. list of endangered and
threatened species. Habitat loss is the single largest threat to these plants and animals. You can find a list of
endangered and threatened species in your state on the U.S. Fish & Wildlife Service website (http://ecos.fws.gov/
tess_public/pub/stateOccurrence.jsp).
Do’s
3 Do locate your new house on land that has already been developed or graded.
Fact: Building on land that has already been developed or disturbed reduces pressure on remaining farmland
and wildlife habitat and makes efficient use of existing infrastructure. Also, brownfields (land formerly used for
industrial or commercial purposes) and greyfields (sites previously developed or graded) may cost less or be offered
for sale with tax incentives.
10
3 Do build your home within an existing community.
Fact: A U.S. Environmental Protection Agency study of San Diego, California, Montgomery County, Maryland,
and West Palm Beach, Florida, found that building in an existing town or city cuts commuting time, reduces air
pollution, lowers travel cost, saves on infrastructure, and improves community quality of life.
See Smart Growth Online (www.smartgrowth.org) to learn about the growing network of government officials,
community activists, and homeowners working to restore vitality to city centers and older suburbs.
3 D
o select a home site that is close to public transportation and bike paths, and that is
within walking distance to stores and other local amenities.
Fact: Car-dependent cities and suburbs are associated with health problems such as obesity, adding as much as
$76 billion annually to U.S. medical expenses. According to an April 2009 estimate, living with one less car in a
household can save $8,670 a year.
11
C h e ck l i s t F o r Gar de n Co nst r u c t ion
A n d R en o vati o n
You can minimize your new landscape’s environmental footprint while maximizing its improvement to your quality
of life. The benefits will continue for many years to come. Material selection is especially important when you’re
creating a new garden or modifying an existing one.
3 B e sure to work through each section of the Landscape For Life site assessment on page 8, collecting all the
necessary information and considering possible design options. Here are some additional things to keep in
mind:
3 If you’ll be working with a landscape designer or landscape architect and/or a contractor, choose
professionals who have experience designing and installing sustainable landscapes.
3 B efore construction begins, protect areas of undisturbed soil and as much healthy native landscape as
possible, especially trees and shrubs, by roping them off.
3 B efore choosing materials for your design, think through these options: Reduce the amount of material
required through downsizing if possible and careful design. Reuse existing or locally salvaged materials.
Choose natural, untreated materials and products made locally, preferably certified by an independent
organization to meet rigorous environmental and health standards. Look for materials made partially or
entirely from recycled material. Use construction methods that make it easy to disassemble structures such as
decks for repair or recycling. See the Materials section of the workbook beginning on page 81 for details.
3 D
esign options may be determined by the materials available, so locate material suppliers before
finalizing your plans.
12
W h at T o A s k W hen Hi r ing A Landscape
D e si g ner O r C o n t r a c t or
Take some time to ask appropriate questions and check references. Those who specialize in sustainable practices
are most likely to be able to help you create a home landscape that’s both beautiful and healthy for people and
the environment.
A landscape designer or landscape architect is the person who works with you to plan and design your garden.
Landscape contractors work under your direction if you design the garden yourself, or under the landscape
designer or landscape architect. Landscape contractors can install trees, shrubs, and other plants as well as
features such as walkways, driveways, patios, terraces, decks, arbors, water features, and retaining walls.
Here are some tips to help you find a qualified professional:
3 T ake some time to research what you would like to see in your garden. A good designer or landscape
architect will listen and feed off of your ideas, and it will make for a better end product.
3 S eek referrals from friends, family, or co-workers who have worked with a landscape designer or contractor to
create a sustainable garden.
3 A sk your local chapter of the U.S. Green Building Council (USGBC) if they can recommend an experienced
landscape professional. Check the USGBC website (www.usgbc.org) to find out how to contact the nearest
chapter.
3 A sk questions. Are the landscape professionals you are considering knowledgeable about sustainable
design and building practices? Have they been involved in a LEED (www.usgbc.org/DisplayPage.
aspx?CategoryID=19) green building project? Are they familiar with the Sustainable Sites Initiative (www.
sustainablesites.org), the green landscape rating system on which Landscape For Life is based?
3 D
o they meet licensing and legal requirements for landscape designers and contractors?
3 A re they insured? Ask to see proof of business liability insurance and workers’ compensation coverage. You
can find yourself liable if an uninsured contractor causes damage or an uninsured employee gets injured on
your property.
3 A re they affiliated with professional groups such as the American Society of Landscape Architects (www.
asla.org) or the Association of Professional Landscape Designers (www.apld.org)? Membership in a trade
organization is no guarantee that you’ll end up being satisfied with your landscape, but it is an indication that
they are serious about their professionalism.
3 R eview their design portfolio and ask questions about how decisions about sustainability were made.
3 A sk for references and check them.
13
Soil
It’s no coincidence that our planet gets its name from soil,
also known as earth. Soil is a critical part of the web of life
that sustains us. It’s the habitat of countless organisms, from
microscopic bacteria to earthworms, that transform wastes into
the food that nourishes plants and animals. Other creatures spend
part of their lives in the soil, like insects, or live partially in it, like
plants. Healthy soil absorbs rainwater, helping to prevent floods,
and cleanses the water as it percolates into the earth. A critical
carbon sink, it also stabilizes the earth’s climate.
Yet modern industrial society has left much of the earth’s
soil eroded, exhausted, and polluted. Too much fertilizer, the
horticultural equivalent of fast food, and other gardening practices
have unwittingly contributed to the problem.
But it is possible to restore and harness the natural soil
food web to create the healthy soil that is the foundation of
thriving garden. This section of the Landscape For Life workbook
shows you how.
The U.S. is losing soil ten
times faster than its natural
replenishment rate due mostly to
erosion by wind and rain.
Conventional And Sustainable Landscapes: How They Compare
Conventional Landscape
Sustainable Landscape
• Soil is often paved or compacted, so rain
• Rain soaks in the soil, nurturing plants and
• Results in soil erosion and pollutes local
• Protects nearby waterways
• Puts the natural soil food web to work for
rushes off
replenishing groundwater
waterways
• Typically receives regular, often unnecessary,
fertility
fertilizer applications
• Garden trimmings are composted or used as
• Garden trimmings get dumped in a landfill
• Costs money for supplemental water, fertilizer,
mulch
• Can save money
and other inputs
14
a
G e t T o K n o w Y o ur Soil
The site assessment for your landscape has identified relatively undisturbed native soil and vegetation that should
be protected. You’ve also located areas where soil needs to be nursed back to health or enhanced, such as in the
vegetable garden, since many edible plants do best in well-drained loam with a fairly neutral pH of 6 to 7 that is
rich in organic matter and able to retain soil moisture and nutrients. Now it’s time to become familiar with the
particulars of your soil.
Soil Basics
Soil is a complex mixture of weathered rock and mineral particles, the living organisms of the soil food web, and
the decaying remains of dead plants, animals, and microorganisms. The living and dead organisms are known as
organic matter. Air and water are also important components of healthy soil. Topsoil is the most biologically active
and productive, upper soil layer. Good garden topsoil is about 45 percent mineral particles, 25 percent air, 25
percent water, and 5 percent organic matter by volume.
According to the U.S. Department of Agriculture:
• Soil scientists have identified more than 70,000 kinds of soil in the U.S. These many types of soil contain
different combinations of mineral particles, such as sand, silt, and clay, and various amounts of organic matter
and nutrients.
• Five to 10 tons of animal life can live in an acre of soil.
• Natural processes can take more than 500 years to form just one inch of topsoil.
Soil Texture
Soil texture—how coarse or fine it feels—depends on the size of the mineral particles. Sand, silt, and clay, the major
mineral particles, are directly responsible for the size and number of the soil’s pore spaces. They determine its level of
air and oxygen, its drainage rate, and how well it holds nutrients.
Sand grains are the largest particles and create large pores. Sandy soils drain quickly and don’t hold water and
nutrients well.
While sand can be seen by the naked eye, silt particles are microscopic. They feel velvety and smooth. They create
smaller pores in the soil and result in better water retention.
Clay particles are the tiniest of all. When moist, they cling together and feel sticky. Clay soils have a tremendous
capacity to hold water and nutrients, and soils rich in clay tend to suffer from poor air circulation and drainage.
Soils are rarely pure sand, silt, or clay but rather a mixture of all three. They’re often grouped into one of 12 textural
classes based on the relative proportions of these particles. Sands and loamy sands, for example, are more than
70 percent sand and share the characteristics of sand. Clays, sandy clays, and silty clays are more than 40 percent
clay and exhibit the characteristics of clay. Loams, the ideal soils celebrated in so much gardening literature, share
the attributes of both—good aeration, drainage, and moisture and nutrient retention. Most vegetables do best in
loamy soil. No matter the texture of your soil, it’s possible to grow beautiful plants, as long as they are adapted to the
particular conditions.
15
SOIL TEXTURE TRIANGLE
100
0
10
90
20
80
70
30
clay
40
cla
nt
rce
pe
20
10
0
silty
clay loam
70
silt loam
sandy loam
80
60
80
loam
loamy
sand sand
100 90 90
100
clay
loam
silt
sandy
clay loam
silty clay
nt
sandy
clay
40
30
50
50
rce
pe
y
60
90
silt
80 70 70
60 60 5050
percent sand
4040
30 30
20 20
10
100
0
Scientists divide soil into 12 textural classes. The soil texture triangle can help determine which class of soil
you have.
• After
doing the jar test on page 17 to tell you the percentages of sand, silt, and clay in your soil, locate the
percentage of clay in your soil on the left side of the triangle and follow the purple line across.
•N
ext, find the percentage of sand along the bottom of the triangle and follow the blue line up to where it
intersects with the purple line you identified.
•T
he green line at this intersection represents the percentage of silt in your soil sample. The shaded area that
contains the point where the lines intersect is your soil’s textural class.
16
How to determine the texture of your soil
The feel test: Rub some moist soil between your fingers. If it feels coarse and gritty, your soil is probably
dominated by sand. If it feels smooth and velvety, you most likely have silty soil. If it clings together and feels sticky, it
probably contains a lot of clay.
The jar test: After removing stones or debris, put 2 cups of garden soil in a quart-size jar. Add 1 teaspoon of liquid
dish soap. Fill the jar to the top with water and close the lid tightly. Gently turn the jar upside down and right-side
up for about a minute to mix. Let it sit for a day so the particles can settle out. Sand will have settled to the bottom,
silt will comprise the middle layer, and clay the top. Measure the thickness of each layer, and divide the number of
inches by 100. This will tell you the percentage of sand, silt, and clay in your soil. Use the soil texture triangle on
page 16 to determine its textural class.
Soil Structure
How readily soil particles cling together to form aggregates is the measure of its structure. This determines how
permeable your soil is, how well it retains moisture and nutrients, and how easily it allows plant roots to penetrate
and grow. Horticulturists consider soils with loose, granular aggregates about the size of cookie crumbs to have good
structure for plant growth.
The key to good soil structure is adding organic matter. To maintain good structure, don’t overcultivate your soil.
How Healthy, Sandy And Compacted Soils Compare
HEALTHY SOIL
SANDY SOIL
COMPACTED SOIL
How readily soil particles cling together to form aggregates, called crumbs or peds, is the measure of soil
structure. Soils that bind together to form loose, granular aggregates about the size of cookie crumbs (left)
retain moisture and nutrients and are well aerated—ideal for the growth of plant roots. The key to this good
structure is organic matter and thriving communities of soil organisms. Sandy soils (center) do not bind
together and tend to have the consistency of cake mix. Compacted soils (right) have a “platy” structure, with
multiple layers of flat, thin peds. Weight bearing down on the soil has caused the larger pores to collapse,
restricting the movement of air and water and limiting the growth of plant roots.
17
How to determine your soil’s structure
The squeeze test: Hold a sample of soil in your hand and examine it closely. Any large clumps should fall
apart under gentle pressure to form cookie crumb-sized aggregates. If they resist crumbling and instead form tight
clods, you likely have heavy clay soil. If they break apart into individual particles, like cake mix, the soil probably is
predominantly sand. However, structure can be related to other factors as well. Big clods may also be an indication
of compaction, even in soils with relatively little clay. Sterile loam soils, in which natural microbial action has been
impaired, are unable to form even small aggregates.
How to determine your soil’s drainage
The percolation test: Dig a hole in your garden about 1 foot wide and deep. Fill the hole to the top with
water.
• If it disappears in an hour or less, your soil has sharp drainage. In the ornamental garden, this means you
should grow plants adapted to dry conditions. In the vegetable garden, adding organic matter to help retain
moisture will enable you to grow a wide range of edible plants.
• If the water drains within a few hours, drainage is good and can support a wide range of ornamental and edible
plants.
• If after 24 hours there is still water in the hole, the water table may be high. In this case you should grow plants
adapted to wet conditions. Or drainage may be poor because your soil has a high clay content, or your soil may be
compacted from trampling or use of heavy equipment. In these latter two cases, working organic matter into the
soil is a remedy, although severely compacted soils may require more radical action (see page 30).
SOIL pH
Soil pH is a measure of the acidity or alkalinity of the water held in its pores. The pH scale goes from 0 to 14, with 7
representing neutral. From pH 7 to 0 the soil is increasingly acidic, while from 7 to 14 it is increasingly alkaline.
Soil pH affects whether minerals and nutrients will be available to your plants. Before a nutrient can be used by
plants, it must be dissolved in the soil solution. Most plants prefer a slightly acid to neutral soil, with a pH of 6
to 7, because that is the range in which all nutrients are readily available. In strongly acidic soils (pH 5.5 to 4),
important nutrients such as phosphorus, potassium, calcium, and magnesium are in short supply. The availability of
phosphorus, iron, copper, zinc, and manganese is reduced in slightly to moderately alkaline soil (pH 7 to 8).
Soil pH also affects the activity of soil microorganisms. Bacteria that decompose organic matter are hindered in
strongly acid soils. This prevents organic matter from breaking down and ties up nutrients, particularly nitrogen.
Strongly acidic or alkaline soils can increase the solubility of some nutrients and minerals to the point that they
become toxic to plants. For example, in very alkaline soils, the levels of calcium and magnesium are so high that they
impede the availability of phosphorus.
How To Determine Soil pH
Home pH testing kits, available at local garden centers, can give you a general idea of your soil’s pH, but the most
accurate way to determine pH is to have the soil professionally tested (see page 20).
If your soil is strongly acidic or alkaline, you should choose plants for the ornamental garden that are adapted to
those conditions. In the vegetable garden, soils can be amended to adjust pH. See page 29 for more information on
acid and alkaline soils.
18
Essential Nutrients
The elements essential to plant health are classified as macronutrients, which are needed in the largest quantities, or
micronutrients, which are required in minute amounts. Both are necessary for healthy plants.
The primary macronutrients are nitrogen (N), phosphorus (P), and potassium (K). The relative proportions of these
nutrients are listed as N-P-K on fertilizer labels.
Nitrogen (N)
Nitrogen stimulates plant root growth and the uptake of other nutrients. Plants deficient in nitrogen tend to be
chlorotic, or pale yellowish green, and stunted with thin, spindly stems.
Most nitrogen is derived from the decomposition of organic matter and nitrogen fixation by bacteria. To
maintain nitrogen levels in fertile soils, mimic natural processes by mulching with compost or other organic
matter. Alfalfa, blood meal, or other natural fertilizers, or nitrogen-fixing green manures can increase the
nitrogen levels of infertile soils. See Fertilizer Tips For A Sustainable Garden on page 23 for details.
Phosphorus (P)
Phosphorus enhances photosynthesis, nitrogen fixation, flowering, fruiting, and seed production. It also encourages
root development. Symptoms of phosphorus deficiency include delayed flowering or fruit set, and a purplish cast on
leaves and stems.
The main source of phosphorus is the decomposition of organic matter. Phosphorus deficiency is common in strongly
acidic or alkaline soils and soils high in aluminum. Manure or liquid seaweed are good renewable sources for
phosphorus-deficient soils.
Potassium (K)
Potassium is known to activate 80 enzymes responsible for basic plant processes such as carbohydrate metabolism
and photosynthesis. It is critical to reducing the loss of water from leaves and increases the ability of the roots to
take up water. Adequate soil potassium is linked to improved drought tolerance, improved winter hardiness, better
resistance to some fungal diseases, and greater tolerance of insect pests. When plants suffer from potassium
deficiency, the tips and edges of the oldest leaves yellow and die and appear burned around the edges.
Compost can help maintain good potassium levels in fertile soil, while kelp meal is a renewable source that can help
raise them in deficient soils. Composted wood ash is another source of potassium, but should be used only on acidic
soils.
Other Nutrients
Other nutrients are considered secondary because they typically are found in sufficient quantities in the soil and no
amendments are required. Secondary nutrients include calcium, magnesium, and sulfur.
Micronutrients or trace elements include iron, boron, copper, manganese, zinc, chlorine, and molybdenum. Except
in highly acidic or alkaline soils, micronutrient deficiencies are generally uncommon, and a balanced supply can be
maintained with regular infusions of organic matter. For more on acidic or alkaline soils, see page 29.
19
Soil Testing
One of the smartest things you can do for your garden
is get your soil tested by a university extension lab or
a commercial lab for about $25 to $40. It can save
you money on unnecessary fertilizer and plants that
are not adapted to your natural soil conditions. A lab
test can help avoid nutrient imbalances from excess
fertilizer that can run off and pollute waterways. It will
also help you determine which plants are best suited
to growing in your garden.
Most soil labs will send you a soil test kit that includes
sampling instructions, a sample bag, and a survey
form. Be sure to fill out the survey in detail so the lab
can make the most informed recommendations for
your property.
Although they can vary somewhat by state, a
standard soil test typically will tell you:
• Soil pH
• Levels of potassium, phosphorus, calcium,
magnesium, and sulfur
• Organic content
• Lead contamination and what to do about it
• Recommended nutrient or soil amendments
Home and professional tests can provide information about
your soil that will help you determine appropriate plant
choices.
If they’re not part of the standard test, levels of nitrogen
and other nutrients, sodium, soil texture, and other factors can be tested for an extra charge and must be specifically
requested. It makes most sense to have nitrogen tested early in the growing season.
Use a lab that is close to home because its experts know about local soil conditions. On the National Sustainable
Agriculture Information Service website (http://ww2.attra.ncat.org/index.php/soil-lab.html) you’ll find a list of
soil test labs that cater to organic and sustainable growers; click on your state to find labs in your area. “Growers”
typically means farmers, not homeowners, so ask the lab to tailor its recommendations for a garden.
You should send off a sample whenever you suspect a problem or every few years.
For More Information
Healthy Soils for Sustainable Gardens (http://shop.bbg.org/mm5/merchant.mvc?Screen=PROD&Store_
Code=BGGS&Product_Code=BBG-TEC-200&Category_Code=BBG-TEC), edited by Niall Dunne and published by
Brooklyn Botanic Garden, is a good basic guide to soil for sustainable gardeners.
20
S l o w F o o d F o r Fe rt ile So il
Fertilizer is the horticultural equivalent of fast food.
Feeding your plants a steady diet of it can be harmful.
Fertilizer is like a shot of caffeine that produces a
temporary burst of energy and growth. But overuse
can destroy the microscopic fungi and bacteria and
larger creatures such as earthworms that are the key
to long-term soil health.
The excess nitrogen and phosphorus in fertilizer is
carried by stormwater runoff to nearby waterways,
where it causes eutrophication, which stimulates
algae growth and removes oxygen from the water,
killing fish. Excess nitrogen in groundwater or
surface waters can harm human health. You can
find out more about these problems on pages 4
and 5. Meanwhile, we ship garden trimmings off to
overburdened landfills, robbing the soil of nutrients
and making more store-bought fertilizer necessary.
Why not mimic nature? In a forest, prairie, or other
natural landscape, nature maintains soil fertility
by transforming fallen leaves and branches into
rich organic matter. Many good sources of organic
matter can be found in your own backyard, including
autumn leaves and garden and lawn clippings.
Compost from your municipality or nearby farmers
and other local sources of organic matter are the next
best thing to those recycled from your garden.
Used as mulch or a soil amendment, compost made
from fallen leaves and other organic materials on your
property may provide most of your plants with all the
nutrients they need.
21
SOIL FOOD WEB
Carbon Dioxide
Solar Energy
Nutrients
organic matter
Nutrients
Released
fungi
bacteria
Primary
Consumers
Nutrients
Released
Secondary
Consumers
protozoa
springtail
mite
nematode
Higher-Level
Consumers
Nutrients
Released
centipede
spider
millipede
ground beetle
ant
earthworm
The soil food web is the key to fertile soil. This diverse community of organisms is grouped together based on their
roles. Plants are the producers—they use the sun’s energy to convert water and carbon dioxide into plant material
via photosynthesis. The primary consumers or decomposers, mainly fungi and bacteria, are capable of digesting
fallen leaves and other organic matter. Secondary consumers feed on them, then release nutrients that can be
absorbed directly by plants, as well as undigested remains that become part of the soil organic matter. Higher level
consumers feed on the secondary consumers. Their fecal pellets become part of the soil organic matter, and they
also release nutrients that spur plant growth.
22
Fertilizer Tips For A Sustainable Garden
The goal of applying fertilizer is to supply just enough to meet your plants’ needs. Too much fertilizer can run off
into nearby waters, leach into groundwater, or lead to weed problems. Your plants’ health should be your guide.
If they suffer from a lack of vigor, retarded growth, sparse foliage, or leaf discoloration, they may be nutrient
deficient, although improper drainage or inadequate aeration are more likely the cause.
What To Do
• Test your soil to determine whether there really is a nutrient deficiency.
• If supplemental nutrients are necessary, choose a renewable natural fertilizer, preferably produced locally, over
synthetic (petrochemical-based) fertilizer or mined products like rock phosphate. Synthetic fertilizers require much
more energy to produce than natural options such as blood meal, bonemeal, fish meal or emulsion, and kelp meal.
• Whenever appropriate, use single-nutrient fertilizers instead of so-called complete fertilizers that contain
nitrogen, phosphorus, and potassium. For example, if your soil is low in nitrogen but not in phosphorus and
potassium, use blood meal, fish emulsion, or other high-nitrogen natural fertilizer. Better yet, grow your own
green manure.
• Add only the amount of fertilizer recommended in your soil test, no more. Follow the guidelines on the fertilizer label.
• Apply fertilizer to the soil, not paved areas, and sweep stray particles into the planting bed.
• Do not use fertilizer near streams or drainage ways.
Compost: Homemade Humus For Healthy Soil
The same natural recycling that happens every day in nature is also at work in a compost pile. Called
decomposition, it can take years in nature. But when you compost, you give fungi, bacteria, and nature’s other
decomposers everything they need to recycle much faster.
An inch-thick topdressing of compost on your planting beds is generally all you need to keep your soil healthy and
provide your plants with a balanced source of nutrients. Compost can also be used as a fix for problem soils (see
page 28). And composting keeps valuable organic materials out of landfills.
Eventually, even the material in a neglected pile will decompose. But a well-managed home compost pile creates
the most nutritious compost. And unlike a neglected pile, it results in little or no emissions of methane or nitrous
oxide, two heat-trapping greenhouse gases.
What To Do
• Locate your compost pile in a well-drained spot on your property that is shaded from the hot afternoon sun.
• Purchase or build a compost bin to keep the organic material in and wildlife out. The bin should be about 4 feet
in diameter and 3 feet high.
• Nature’s recyclers need a balanced diet of carbon (C) and nitrogen (N). Fill the bin with alternating layers of
high-carbon “brown” materials, such as leaves, newspaper, and chipped woody trimmings, and nitrogen-rich
“green” materials, such as grass clippings and other green garden trimmings and kitchen scraps. This will
provide the C:N ration of 30:1 that will conserve the most nitrogen and carbon in the finished compost.
• Nature’s recyclers also need air and moisture. Turn your pile with a garden fork as often as necessary to keep
the materials damp to the touch, like a wrung-out sponge. If they’re wet, turn the pile to increase aeration.
However, too much air will dry out the pile and slow decomposition. If it feels dry, add water as you turn over
the pile.
23
• Maximize airflow by shredding materials before adding them to the bin, and by building your compost pile on a
foundation of wood chips or other coarse organic material.
• It’s a good idea to have two compost piles—a full pile that is “finishing” and another for adding new material.
• Finished compost is dark in color and smells earthy, like soil. Usually, it’s difficult to recognize any of the original
ingredients. But there’s no single point at which compost is finished—it depends on how you want to use it. For
most garden applications, it’s fine to use compost that still has a few recognizable bits of leaves or twigs, which
will finish rotting in the soil. If you plan to use compost in seed-starting mixes, it may be better to use highly
finished compost.
Brown leaves
Kitchen
scraps
Straw
Grass clippings
Brown leaves
Green leaves
Wood chips
The decomposing organisms that transform garden “wastes” into compost need a balanced diet of carbon and
nitrogen. A healthy compost pile has alternating layers of high-carbon “brown” materials, such as dry leaves,
straw, and chipped woody trimmings, and nitrogen-rich “green” materials, such as fresh grass clippings and
other “wet” or green garden trimmings and kitchen scraps. To encourage air flow, it’s a good idea to build your
compost pile on a foundation of wood chips or other coarse organic material.
24
Organic Mulches And How To Apply Them
When you mulch, you’re basically mimicking one of nature’s fundamental processes. Many plant communities
naturally generate healthy layers of organic litter.
Consider what happens in a deciduous forest, one of nature’s champion mulchers. The leaves shed in autumn are
transformed by the soil’s natural food web into plant food and the rich organic matter called humus that is the key
to maintaining healthy soil. The blanket of organic matter protects plants from extremes of temperature, prevents
soil erosion, and conserves soil moisture that otherwise would evaporate.
Mulching provides your garden with these same benefits and more.
• Mulch conserves water—no small matter given that the proportion of municipal water used for garden irrigation
is 30 percent in the eastern U.S., and can be 60 percent or more in the West.
• Mulch keeps the soil around plant roots from frying in summer and in winter helps prevent alternate freezing
and thawing, which causes root damage.
• By cushioning the impact of downpours, mulch also helps prevent soil compaction, allowing water to penetrate
and plant roots to breathe.
• Over time, organic mulches decompose and add nutrients and organic matter to your soil, improving water
retention and nurturing the soil fauna that promote fertility.
• By creating the conditions that help them thrive, mulch makes your plants less vulnerable to pests and diseases.
• It also suppresses weeds, making life easier for you. And because mulch keeps the soil loose, there’s no need for
regular cultivation with hoe or scuffle.
Inorganic mulches, such as crushed stone and recycled rubber chips, are appropriate for rock gardens, driveways,
and paths. They can also be a good choice for gardens in arid regions, where organic mulches may constitute
a fire hazard or be difficult to produce locally. In most climates and situations, however, organic mulches are
preferable for planting beds because they eventually break down and enrich the soil.
Bagged mulches are commercially available, but you can save money and make your garden function more
ecologically by mulching fallen leaves and other organic materials from your own property. Recycling them in your
yard also keeps them out of the local landfill.
How To Apply
• Most mulches should be about 3 inches deep for best results (see Some Recommended Organic Mulches on the
page that follows).
• The optimum mulch depth also depends on your soil type. Sandy soil, which loses moisture rapidly, benefits
from a thicker mulch than clay soil, which tends to retain water.
• Before applying mulch, pull any existing weeds or smother them with a layer of newspaper, then water well.
• To avoid diseases, pull the mulch back an inch or two from your plants.
• The best time to spread mulch around heat-loving vegetables like peppers and tomatoes is after the soil has
warmed, usually mid- or late spring. Cabbages, greens, and other cool-weather crops can be mulched earlier.
Mulches around shrubs and perennials will offer the best protection against winter cold if laid down in early
winter, when the soil has cooled but not frozen hard—recycled holiday trees and trimmings are great for this
purpose. Mulch can be applied anytime in herbaceous perennial beds and around trees and shrubs.
• Don’t mulch seedlings planted in very moist soils because excessive wetness is an invitation for damping-off,
25
an often fatal fungal disease. Once seedlings are
established, it’s safe to mulch.
• Because organic mulches eventually break down
and become part of the soil, they need to be
renewed every two or three years, depending on
your climate and the type of mulch you use.
Some Recommended
Organic Mulches
• Leaves
Leaves make a great mulch, and they’re also
free. Apply a layer 2 to 3 inches thick. Partially
shredded leaves are less likely to mat and shed
water than whole leaves, so run your rakings
through a leaf shredder or pass the lawn
mower over them a few times before mulching.
Composting leaves with a lot of cellulose that
are very slow to break down, such as oak leaves,
with some grass clippings for a week or two will
improve the mulch.
• Bark
Applying organic mulches promotes soil fertility.
Bark mulches should be applied 3 to 4 inches deep. Because they’re a recycled byproduct of the lumber
industry, they’re preferable to wood chips, which may be made from trees felled solely for the manufacture of
mulch. Look for products expressly labeled “bark mulch,” not just wood or hardwood mulch.
ood chips
•W
When obtained from local arborists who create them from their daily prunings, wood chips are a good choice
and may even be available for free. Three to 4 inches is the proper application depth. There is some evidence
that freshly chipped wood can rob nitrogen from soil. Compost them first, or let them “season” in a pile for a
few weeks, especially if you will be using them in the vegetable garden.
ine needles
•P
Pine needles are light and fluffy and don’t get compacted, so water penetrates easily. Apply a layer 4 to 6
inches thick. Because they tend to lower soil pH, they’re best used around acid-loving plants.
• Nutshells
If nutshells are an agricultural byproduct in your area, they are a good choice. Apply them about 2 inches deep.
Shells tend to look a bit more formal than other mulches. Beware of cocoa hulls, a by-product of chocolate
processing, which contain compounds toxic to dogs.
• Straw
Applied 6 to 8 inches deep, straw is an effective mulch, but be sure you get straw and not hay, which can be
full of weed seeds. Straw isn’t very attractive in perennial planting beds but looks appropriate in the vegetable
garden.
• Compost
Topdressing your planting beds annually with an inch of compost will provide most of your plants with a
balanced source of nutrients.
26
Green Manures And How To Use Them
Growing “green manures”—grains and legumes used as cover crops—is a good way to increase the amount of
organic matter and nutrients in your soil. Cover crops reduce the need for fertilizer. They also help aerate the soil,
increase its capacity to conserve moisture, and protect it from being pounded down and compacted by raindrops
and eroded away by water or wind. And they help suppress weeds.
Grains such as wheat and oats are especially good at increasing soil organic matter. In addition to adding
organic matter, leguminous cover crops, like alfalfa, clovers, or cow peas, which contain nitrogen-fixing bacteria
in their root nodules, remove nitrogen from the atmosphere and make it available in soil. A healthy planting of
leguminous cover crops can supply half or more of the nitrogen needed by the next crop.
Growing Tips
• Most gardeners use green manures to cover bare vegetable beds in winter.
• For multiple benefits, grow grains and legumes together.
• To get them off to a good start, plant winter cover crops at least 4 weeks before the expected first hard frost
date in your area.
• Plant cover crops with large seeds, like peas, in shallow, closely spaced furrows. Broadcast those with small
seeds, then rake lightly to cover.
• If the weather is dry, water to keep the soil lightly moist until the young cover crop is established.
• Till cover crops into the soil in spring, just before flowering, or about 3 weeks before planting to give the organic
matter time to start breaking down.
• Avoid cover crops that are invasive in your region.
For More Information
National Sustainable Agriculture website (http://ww2.attra.ncat.org/index.php/covercrop.html) is a good
source of detailed, state-by-state information on green manures—so long as you are carful not to use a weed as
a cover crop!
27
D e a l i ng With “ Pr o b le m So ils”
If you choose the right plant for the site, there’s rarely such a thing as a “problem soil.” Too often, gardeners try
to grow plants that are not adapted to the site, then need to modify the soil and provide the missing water or other
element on a continuing basis.
In the ornamental garden, if you choose plants that are suited to your soil conditions, you will rarely have a
problem. Vegetable gardening, however, may be improved with a deep, well-drained yet moisture retentive,
humus-rich soil. Soils that have been disturbed by human activities also often require special treatment. In these
situations, improve the soil with organic matter recycled from your garden whenever possible.
Sandy Soils
Plant roots can grow with ease in sandy soils, but water drains quickly and nutrient ions do not readily bind to sand
particles. As a result, sandy soils can lack moisture and nutrients.
What To Do
• Grow drought-tolerant plants that adapt well to soil with low fertility. In California, for example, good choices
include lavenders (Lavendula), California lilac (Ceanothus), and California poppy (Eschscholzia californica).
Check with your local botanic garden (http://www.publicgardens.org/gardens) or other public garden for plant
recommendations.
• In the vegetable garden, incorporate organic matter in the soil to improve water retention. Organic matter
decomposes relatively quickly in sandy soils, so add a mix of materials that provide a quick infusion of humus,
like compost, and others that break down more slowly, such as straw or shredded bark.
• Mulch planting beds to help retain water.
• Because nutrients tend to leach out of sandy soils, water more sparingly yet frequently to give plant roots the
moisture they need and minimize leaching.
• Grow green manures to add organic matter and nitrogen to sandy soils.
Clay Soils
Clay soils lack good drainage and aeration and compact easily. When dry, they can be hard as cement. However,
clay soils are generally quite fertile.
What To Do
• Grow plants adapted to heavy soils. Purple coneflower (Echinacea purpurea), prairie blazing star (Liatris
pycnostachya), and lanceleaf coreopsis (Coreopsis lanceolata), for example, are good choices for the Midwest
and Southern Plains. Check with your local botanic garden or other public garden for plant recommendations.
• In the vegetable garden, improve aeration and drainage by working organic matter into clay soil. Adding coarsegrain sand also improves aeration, but sand is a nonrenewable resource and often not sustainable because it
needs to be added in large amounts to have beneficial effects.
• Use a fork rather than a shovel when cultivating clay soil is necessary.
28
• To avoid compacting clay soil, work it only when it is moist, not dry or wet. Let large clods air dry before
breaking them up with a rake.
• Apply mulch to maintain organic matter levels. Mulch also helps minimize compaction from pounding rain and
shields the soil from the baking sun.
• Install pathways in the garden to minimize compaction from foot traffic.
• Irrigate clay soils slowly to avoid waterlogging.
Wet Soils
In wet or poorly draining soils, pore spaces are waterlogged and aeration is poor. Most plants cannot function
properly in constantly wet soil and suffer from disease, decline, and eventual root death.
What To Do
• Grow plants adapted to wet soils. In the eastern states, for example, river birch (Betula nigra), summersweet
(Clethra alnifolia), and astilbes (Astilbe) are appropriate choices. Check with your local botanic garden or other
public garden for plant recommendations.
• Grow vegetables and herbs in raised beds.
• Divert rain water from your gutters into a rain garden.
Acid Soils
Acid or “sour” soils are common in the eastern U.S. where rainwater leaches calcium and magnesium from the soil
and acid rain and fertilizers acidify the soil. Most garden plants do best in slightly acidic soil, with a pH of 6.2 to 6.8, but
typically can tolerate levels as low as 5.5. If you haven’t already done so, have your soil tested to determine its pH.
What To Do
• Grow plants adapted to acidic soils. Azaleas and rhododendrons (Rhododendron), hydrangeas (Hydrangea),
and bayberries (Myrica), for example, are good choices in the East. Check with your local botanic garden or
other public garden for plant recommendations.
• Use animal manure, leguminous cover crops, compost, or wood ash to help raise your soil’s pH. Mix in 1 to 3
inches of compost, then mulch with the same amount every year. Wood ash is very high in potassium, so check
with your local Cooperative Extension office (www.csrees.usda.gov/Extension/) about how much to apply.
• Adding finely ground limestone is the conventional, if less sustainable, prescription for acid soils. If you decide
to go this route, follow the recommendations in your soil test report. Neutralizing soil pH with lime takes about a
year and needs to be repeated after a few years.
Alkaline Soils
The pH of alkaline or “sweet” soils is higher than neutral, or 7. These soils are common in arid regions like the
southwestern U.S., where evaporation exceeds precipitation and calcium and magnesium accumulate in the soil.
Nitrate-based fertilizers can also raise soil pH. When soil pH is higher than 8, the solubility of nutrients is reduced,
so they are not available to plants. If you haven’t already done so, have your soil tested to determine its pH.
29
What To Do
• Purchase plants adapted to alkaline soils. In the Midwest, for example, eastern persimmon (Diospyros
virginiana), redbud (Cercis canadensis), and boxwoods (Buxus) are appropriate choices. Check with your local
botanic garden or other public garden for plant recommendations.
• Compost made from oak leaves or sawdust and other wood products can gradually lower soil pH.
• Grow vegetables and herbs in raised beds in compost-rich soil.
• Mulch with pine needles or shredded pine bark, which help acidify the soil.
• Incorporating mined sulfur, sometimes called “flowers of sulfur,” into the soil is the conventional prescription for
acidic soils. However, this is a non-renewable product and not truly sustainable. If you decide to go this route,
follow the recommendations in your soil test report for how much to apply.
Compacted Soils
Healthy soil typically has more than 40 percent pore space, ranging from large pores, which promote drainage,
to small pores, which help store water. This combination enables air and water to penetrate, promotes good
drainage, and allows soil organisms to breathe and plant roots to grow. Compaction by machinery, foot traffic,
and pounding rain makes life in the soil difficult. Compacted soils can flood and also be droughty, since water
runs off rather than infiltrating, potentially damaging waterways. Repair compacted soil by rebuilding its spongy
structure.
What To Do
• Top-dressing your planting beds with an inch of compost will improve lightly to moderately compacted soils.
Earthworms and other soil fauna will gradually pull it down into the soil, making it looser and better able to
absorb water. A 2- or 3-inch layer of shredded leaf mulch or wood chips, preferably obtained from a local
arborist or your own backyard, will have the same beneficial effects.
• Cultivating the soil lightly and incorporating compost can speed up the healing process.
• More extreme physical aeration may be necessary to repair highly compacted soils. Consider hiring a
professional landscaper to do vertical mulching—drilling deep holes in your planting beds or around your trees
and backfilling them with compost.
• Create pathways and use garden walls, fences, or mulches to keep foot traffic off the soil.
Shallow Soils
Shallow soils constrict plant roots, may be nutrient-deficient, and tend to dry out very quickly. They typically consist
of a thin layer of soil on top of a dense, clay subsoil or rock. But they can also be caused when builders scrape
away the topsoil at a construction site.
What To Do
• If your topsoil is naturally thin, grow shallow-rooted, drought-tolerant plants adapted to rocky habitats. In the
Pacific Northwest, for example, alpine aster (Aster alpinus), Harebell (Campanula rotundifolia), and meadow
pink (Dianthus deltoides) grow naturally in shallow soils. Check with your local botanic garden or other public
garden for plant recommendations.
• Grow vegetables in raised beds.
30
• To repair soils around recently constructed homes, incorporate compost and green manures, and mulch with
shredded leaves or bark or other organic material.
Saline Soils
Saline soils are often found in arid, poorly drained, and coastal regions. In arid areas with a high water table,
dissolved salts are pulled up from the groundwater by capillary action. These soils tend to be alkaline. In coastal
areas, wind-carried salt builds up in the soil. Fertilizers can also increase salinity, and in some areas the use of salt
on roads can contribute to the problem.
What To Do
• The simplest course of action is to grow salt-tolerant plants. Redbuds (Cercis), summersweet (Clethra alnifolia),
common lilac (Syriga vulgaris), and phlox (Phlox), for example, are good choices in the East. Check with your
local botanic garden or other public garden for plant recommendations.
• In arid areas, mulching lessens salt accumulation by reducing evaporation at the soil surface. But avoid
mulching with animal manures or other organic materials that are high in salt or those, like wood ash, that raise
soil pH.
• If drainage is poor, incorporate compost or other organic materials that are low in salt into your soil.
Contaminated Soils
Soil pollution is caused mainly by industrial wastes and emissions, car exhaust, pesticides, and peeling paint.
Among the contaminants most commonly encountered by gardeners are pesticides and heavy metals.
Because of their widespread industrial use, heavy metals are ubiquitous and increasingly found at toxic levels in
the environment. Lead paint and leaded gasoline were banned decades ago, but there is a risk that your soil may
still contain toxic levels of lead, especially if you live in or near a house or building painted before the late 1970s
or near a busy roadway. If you live near a smelter, contamination by mercury and arsenic may pose a problem.
Pesticides used before World War II often contained arsenic, copper, and lead, which may be an issue on former
farms and especially orchards.
Chronic exposure to heavy metals, either by direct contact with the soil or by eating food grown in contaminated
soil, can harm your nervous system and major organs. In the case of lead, the risk is primarily from exposure to
dust or ingestion of tainted soil by children. Most of today’s pesticides degrade more quickly than older pesticides
such as DDT, but overuse or misapplication can damage your plants and soil fauna.
What To Do
• If your garden is at risk, have it tested for specific toxins, based on the likelihood of past contamination.
Testing for pesticides can be prohibitively expensive, however, so proceed only if there is strong evidence of
contamination.
The following steps are helpful for soils with low-level contamination:
• Add compost to the soil.
• To minimize plant uptake of heavy metals, keep the soil’s pH close to neutral.
• Mulch to keep the contaminants in place and minimize direct contact with the soil.
• Grow produce in containers or raised beds with contaminant-free soil.
31
• Wash your hands after working or playing in the garden.
• If your soil is highly contaminated, you should have it treated or removed and disposed of safely by
professionals. Contact your state department of environmental protection about how to proceed. A list of state
environmental agencies is here (www.epa.gov/epahome/state.htm).
32
S ustai na b l e P o t t ing Mi x e s
Unless you’re new to gardening, you probably remember when many people made potting soil themselves, using
a few readily available ingredients. Nowadays, many gardeners purchase pre-bagged mixes, typically upscale
combinations of largely unnecessary components from around the globe. The amount of energy required to
manufacture and ship these products and the pollution that results can be substantial.
A more sustainable potting mix could easily come from local sources such as composted clamshells, pine bark,
or garden trimmings rather than Canadian peat moss and perlite transported from the Greek island of Milos.
Harvesting peat moss—the remains of sphagnum moss from bogs—destroys the habitat for wetland plants and
animals and releases enormous amounts of carbon dioxide, the major greenhouse gas. A huge amount of energy
is required to produce perlite, because the raw product, a type of volcanic glass, needs to be heated to 1,600
degrees Fahrenheit to become the lightweight pellets used to promote air circulation in potting mixes.
Most pre-bagged potting soil also contains synthetic fertilizer. Container plants typically require more added
nutrients, but a mix enriched with compost or worm castings can often provide them.
The resulting mixes are packaged in plastic bags, then stacked and shrink-wrapped on wooden pallets for shipping
to nurseries and superstores, consuming still more energy and resources.
What To Do
• Make your own potting soil, using compost but not peat or perlite. A classic all-purpose recipe called for 1⁄3
mature compost that has been screened, 1⁄3 garden topsoil, and 1⁄3 sharp sand. These days it’s possible to
use recycled ingredients including compost, worm castings, shredded pine bark, and coir dust, a renewable
material made of coconut fiber. Compost, for example, not only is nutrient rich, reducing the need for additional
fertilizer, but also retains water better than peat. Coir breaks down more slowly than peat, so the product lasts
longer. It is imported from Asia, so energy is required to ship it to North America. However, coir is typically dried
and compressed, then transported by large container ships, which are relatively energy-efficient. Rice hulls are
an alternative to coir in some areas.
• When buying pre-bagged potting mix, check labels to make sure it doesn’t contain peat moss or perlite but does
include compost, preferably compost made locally.
• When you are growing vegetables or other heavy feeders in containers, you may need to use fertilizer to provide
additional nutrients. If so, organic fertilizer, applied sparingly, is preferable to synthetic (petrochemical-based)
products. For more information on using fertilizer judiciously in a sustainable garden, see page 23.
33
G a r d en i ng In R aise d Be ds
A raised bed is basically just a box frame made of wood or other material and filled with soil that has been
enriched with compost or other organic matter. Depending on the material used for the frame, it can be
constructed in various shapes and different depths.
Although raised beds require an initial investment of time and money, in many garden situations this is more than
outweighed by their numerous benefits:
• Raising your planting bed above ground level immediately improves drainage.
• Problems often associated with ground-level gardening, such as erosion and compaction, are eliminated. With a
raised bed, you can plant, maintain, and harvest without ever stepping foot on the soil.
• Raised beds are also a good solution for gardening in wet, shallow, or contaminated soils.
• Because the beds are elevated, it’s easier to promote soil fertility by renewing compost and other organic
mulches, at the same time improving soil moisture retention.
• Raised beds can put an end to aches and pains for people who love to garden but have trouble with their knees
or back, and they can make gardening possible for those with limited flexibility or mobility.
• Raised beds warm up early in spring and stay warm later in the fall, so you can plant earlier and harvest later.
• Carrots and other root vegetables do especially well in raised beds because there are no stones to hinder their
development.
• Raised beds are also good places to grow plants such as mints that can be overly aggressive when their growth
is unrestricted by a soil barrier.
How To Build A Raised Bed
• Construct the frame with a nontoxic material—avoid wood that has been treated with toxic chemicals or
creosote. Untreated wood or stone harvested or obtained locally are good choices. You can find more on
sustainable materials to use in your landscape beginning on page 81.
• If you’ll be growing vegetables, a raised bed should be at least 8 to 12 inches high (deep). For large or deeprooted plants, deeper is better, but beds higher than two feet may require a retaining wall or extra support.
If you’re using wooden boards, secure them at the corners with metal braces or screws, or nail them to a
reinforcing block of wood located in the inside corners.
• Don’t make your raised bed more than 4 feet wide so that you’ll be able to maintain it without stepping in.
How To Garden In A Raised Bed
• In many cases you can simply amend the native topsoil beneath your bed with compost and other organic
materials such as coir or shredded bark increasingly being used in sustainable potting mixes. If the native soil
underneath the bed is compacted, break it up before filling so it does not become a barrier to good drainage.
• If you’re creating a raised bed over contaminated soil, you need to create a barrier between the toxins and the
clean, new soil. Before filling, cover the bottom of the raised bed with landscape fabric that will allow air and
water movement through the bed but prevent plant roots from reaching the tainted soil below.
34
WATER
So much of the earth is covered with water, it’s sometimes called
the “water planet.” About 97 percent of the water is ocean
saltwater. Most freshwater is locked up in the polar icecaps.
Only .003 percent of the earth’s water is available for human
consumption.
Water is chronically in short supply in arid areas, and can be
scarce even in places that historically have had a lot of rain. Yet
we often lavish it on our landscapes—typically drinking water,
which we pay a lot of money to treat and pump. Meanwhile,
instead of capturing and using rainwater in our gardens, we’ve
created an entire infrastructure of gutters, downspouts, and
sewers to get rid of it. The resulting stormwater runoff can
contaminate local waterways with fertilizers, pesticides, and other
pollutants.
The good news is that it’s possible to harvest enough non-potable
water to meet landscape needs and prevent polluting stormwater
from running off our properties.
Information on selecting plants adapted to the precipitation
patterns in your area, alternatives to drinking water for irrigation,
and how to irrigate efficiently follow. For details on organic
mulches and how to use them to conserve water, see page 25.
Public water supply and
treatment facilities consume
enough electricity to power more
than 5 million homes for a year.
In most cities, pumping and
treating water and wastewater
accounts for 25 to 50 percent of
the entire municipal energy bill.
Conventional And Sustainable Landscapes: How They Compare
Conventional Landscape
Sustainable Landscape
• Treats rainwater as a waste to be removed from
• Manages rainwater as a resource to be used on
• Can generate stormwater runoff that pollutes local
• Designed to keeps stormwater on site and
• Usually irrigated with municipal drinking water
• May result in high water bills
• Irrigated with alternatives to potable water
• Can be cheaper to maintain
the site
the site
protect local waterways
waterways
35
C r e at e A Water -Thr ift y La ndsc a pe
Americans consume more than 7 billion gallons
of water a day outdoors. One to two thirds of the
drinking water we use is for irrigation.
It is a popular misconception that this is the only
way to have a healthy lawn and garden. A beautiful
landscape can be in tune with the amount of
precipitation that falls naturally in the area.
Sometimes irrigating makes sense. New transplants
need to be watched carefully throughout the first
year and watered when the soil dries out or the
plants look stressed. In arid climates, gardens may
go dormant and look brown in summer without some
supplemental water. Vegetables often require more
moisture than nature provides via rainfall.
Information on selecting plants adapted to the
precipitation patterns in your area, alternatives to
drinking water for irrigation, and how to irrigate
efficiently follow. For details on organic mulches and
how to use them as a water conservation measure,
see page 25 in the section of the workbook on
sustainable soil practices.
Rainfall flowing off a home’s roof into a rain barrel is used to
irrigate the garden.
How Low Should You Go?
You can measure your progress against benchmarks used in the Sustainable Sites Initiative
(SITES) (www.sustainablesites.org), the new rating system for sustainable landscapes on which
Landscape for Life is based. SITES awards two points for gardens that reduce the use of potable
water by 75 percent from a local baseline case. Three points are awarded for gardens that use
no potable water for irrigation once plants are established, and a garden that consumes no
potable water both during and after establishment is awarded five points.
36
Select Plants Adapted To Local
Precipitation Patterns
Growing plants adapted to the conditions found on your property is one of the basic principles of sustainable
gardening. You’ll find a detailed discussion on how to choose the right plant for your site on page 53.
Following are some tips to help you create a garden that’s suited to local precipitation patterns:
• Preserve as many well established trees and shrubs as possible, because they generally require less water than newly
planted specimens.
• When selecting plants, avoid those labeled “hard to establish,” as they often require large amounts of water.
• Favor plants native to your region, which are adapted to the local climate. Be sure to choose native plants that match
the specific conditions at the planting site.
• If you’re considering a non-native plant, make sure it is not a known invasive species in your region. Some invasive
plants are water guzzlers and can transform the natural hydrology of natural areas, making it even more difficult for
the native species to survive.
• To speed establishment and minimize water use, plant at the recommended time for a particular species. They key
to successful transplanting is getting the roots to grow into the surrounding soil as soon as possible. For many plants
in areas with regular rainfall in the warmer months, this is in spring, when roots are growing most actively and there
is enough moisture in the soil to support new growth. In warmer areas, fall is a much better planting period, and
the best time to plant many woody species is when they are dormant in the winter. Consult plant labels or your local
nursery or public garden (http://www.publicgardens.org/gardens) about the best time to plant.
• The size of your lawn and what type of turf grass you grow can have a huge impact on the amount of irrigation your
landscape requires. Read more about creating a regionally appropriate lawn on page 68.
Use Alternatives To Municipal Drinking Water
For Irrigation
With a little ingenuity, you can use non-potable water from a variety of sources both indoors and outdoors to
irrigate your garden. Non-potable water is not fit for humans to drink, but is generally safe for plants. According
to the American Water Works Association Research Foundation, households that irrigate with alternative water
sources can slash their water bills by as much as 25 percent.
Rainwater Collection
Rainwater collected in barrels or other storage tanks has been used for irrigation for centuries. Rain barrels are
connected to the downspouts of a home’s roof gutters and typically hold around 50 gallons. They come with a
screened cover and an overflow spout and hose to divert excess water away from the home’s foundation. The
typical house has at least four downspouts, at each corner of the house, and rain barrels can be connected to one
or more of them. Of late, designers have been creating versatile variations on the rain barrel, including models
with sleek profiles that can fit along narrow passages, under decks, or in other underused spaces. Modular designs
enable you to add on capacity or even put the tanks in multiple locations.
Cisterns, storage tanks made of stone, mortar, plaster, or cement, were once very common in the U.S., especially in
rural areas where homes relied on private wells for water. Today, prefabricated cisterns are available in various materials
and sizes. A cistern is a more complicated undertaking but can store a lot more water than a rain barrel. Check with the
nearest Cooperative Extension office (www.csrees.usda.gov/Extension/) for information on the best systems for your
region and how to construct them.
37
For More Information
Other useful resources on harvesting rainwater are U.S. EPA’s rainwater collection handbook (http://www.
epa.gov/npdes/pubs/gi_munichandbook_harvesting.pdf) and the American Rainwater Catchment Systems
Association (www.arcsa.org/content.asp?pl=6&contentid=6).
Many states also have resources on rainwater collection. See, for example:
Texas Water Development Board (http://www.twdb.state.tx.us/iwt/rainwater.asp)
Rainwater harvesting case study for Florida (http://www.harvesth2o.com/floridahouse.shtml)
Rainwater harvesting at North Carolina State University (http://www.bae.ncsu.edu/topic/waterharvesting/)
Collecting Air Conditioning Condensate
Condensate is produced when warm, moisture-laden air passes over the coils of an air-conditioning system. The
average single-family home produces 5 to 10 gallons of condensate per day.
Condensate is an attractive irrigation option for several reasons. It’s produced through the normal daily operation
of air-conditioning equipment. Unlike rain, which is sporadic and unpredictable, condensate is produced
regularly during the hottest months when the need for irrigation is greatest. Inquire about the components of a
condensate collection system at local home improvement centers and farm and ranch supply stores. For more
on collecting and reusing air conditioning condensate, see the Alliance for Water Efficiency website (www.
allianceforwaterefficiency.org/Condensate_Water_Introduction.aspx).
Water From Dehumidifiers
Water pulled from the air by dehumidifiers is a high-quality source of water for irrigation. Because the water
typically ends up in a basin that is easily removed for emptying, no additional equipment is necessary.
Graywater Collection
A variety of appliances and fixtures produce used water called graywater. An estimated 50 to 80 percent of
residential “wastewater” is dish, shower, sink, and laundry water. Because graywater often contains soaps,
detergents, shampoos, or other substances as well as bacterial and other pathogens, its use is regulated by state
and local governments (see below).
Graywater is most often recommended for subsurface irrigation of non-food plants. Graywater systems vary from
simple and low-cost to complex and costly. The simplest way to collect graywater is to plug the drain and employ
a bucket to transport bath or shower water for use outdoors. Another common practice (but illegal in some
locations) is to drain the washing machine directly onto outside vegetation. Sophisticated systems involve separate
plumbing for graywater as well as settling tanks and sand filters to remove solids and pathogens.
State And Local Regulations
States and local governments have different regulations on what kinds of graywater are permissible for use. Some
prohibit the collection of graywater entirely, so be sure to investigate what qualifies as graywater and whether any
restrictions apply in your area. A list of some states and municipalities with graywater policies can be found here.
(www.oasisdesign.net/graywater/law/index.htm)
Different Systems For Different Climates
Keep in mind that different alternatives make more sense in some regions than others. For example, harvesting
rain flowing off the roof in rain barrels or other storage systems may be cost effective in rainy climates, but in
parts of the country with dry summers, rainfall may be too infrequent to make them worthwhile. In these areas,
capturing condensate from an air conditioning system is a better option.
38
A Guide To Water-Thrifty Irrigation
Conventional irrigation practices waste a lot of water. Irrigating with traditional sprinklers or when it is hot or windy
leads to water loss through evaporation. Watering too quickly or too much leads to runoff. The goal of water-wise
irrigation is to reduce these losses but still supply as much water as is necessary.
What To Do
• I rrigate only when your plants need water.
How often to water depends on a number of factors, including what type of soil you have, the type of plants
you’re growing, whether your plants are established, the season, and weather conditions. Don’t irrigate on a
fixed schedule, which wastes water by providing it when your plants don’t need an extra drink.
Frequent, shallow watering leads to weak, shallow-rooted plants. Less frequent, deep watering encourages roots to
grow deep, where the soil stays moist longer.
se a rain gauge and/or soil moisture probe.
•U
A variety of relatively simple tools can help you determine when you need to water. The simplest and most
inexpensive of all is a rain gauge to measure weekly rainfall. Soil moisture probes employing different
technologies are commercially available at varying prices. They measure the moisture level of your soil, giving
you a more precise indication of how much, if any, water your plants require.
Rain gauges and soil moisture probes should be used in conjunction with basic knowledge about how much water
various parts of your landscape require. For example, vegetables generally need more than established woody plants.
And even edible plants require less water when it is overcast and relatively cool than when it is sunny and hot.
and water.
•H
According to an American Water Works Association
(AWWA) Research Foundation study, manual
watering with a hand-held hose tends to conserve
more water than other irrigation methods.
If you are going to have an in-ground system, make
sure it is a drip system as it used the least amount
of any automatic system—but still 16 percent more
than watering by hand. In-ground spray systems used
35 percent more water than hand watering, and an
automatic spray system used 47 percent more.
se drip irrigation systems or soaker
•U
hoses.
Drip irrigation systems deliver water through tubing
and emitters placed alongside your plants. The
emitters slowly drip water into the soil in a plant’s
root zone where it is needed, not in gaps between
plants where it is wasted. They also reduce water
loss due to evaporation, and the low flow rate
minimizes the potential for water leaching below
the roots or running off the surface. Drip irrigation
can be used in vegetable and flower beds and
around trees and shrubs.
Watering by hand conserves more water than any other
irrigation method, according to a study by the American
Water Works Association. The same study also found that
drip irrigation consumes much less water than the in-ground
spray irrigation systems used in most home gardens.
39
As the AWWA study discussed above shows, however, drip systems must be operated properly to be truly waterthrifty. To maximize their efficiency, install climate-based controllers such as sensors that prevent the system from
turning on during and immediately after rainfall. Even better are sensors that activate irrigation only when soil
moisture drops below a pre-determined level. So-called “smart” or weather-based irrigation controllers take into
account a range of factors to determine when supplemental water is necessary, including temperature, rainfall,
humidity, solar radiation, and soil moisture levels.
Soaker hoses, which have perforations that slowly leak water into the ground, can also be efficient and effective.
If you’re in the market for a water-conserving irrigation system, it’s worth checking out WaterSense. (www.epa.
gov/WaterSense/) Sponsored by the U.S. Environmental Protection Agency, the program seeks to do for irrigation
products and services and plumbing fixtures what the Energy Star label has done for electric appliances. Irrigation
technologies and services that have been awarded the WaterSense label are listed on the program’s website.
se alternatives to potable water for irrigation.
•U
Take advantage of the various sources of non-potable water around your home. See page 37 for details.
ater your plants early in the morning.
•W
Mornings are cooler, so water doesn’t evaporate as readily as it does in the heat of the afternoon. Evenings are
cool, too, but water sitting on leaves overnight can cause fungal diseases.
For More Information
The Irrigation Association website (www.irrigation.org/) has a section for consumers with tips on how to hire an
irrigation contractor, when an irrigation designer is necessary, and “smart” technology that saves water, time,
and money.
40
S m a rt S t r at e gies For
Ma n a g i ng S to r mwat e r
In a natural landscape, the soil and vegetation absorb
precipitation like a sponge. In developed areas,
however, much of the land has been paved over, and
the soil itself is often compacted and impervious. The
amount of rainfall exceeds the land’s ability to absorb
it, resulting in stormwater runoff.
Rainfall flows from our roofs to gutters and
downspouts, over compacted lawns and driveways
into roads, and down storm drains. In most older
cities this stormwater can overwhelm sanitary
sewers, sending raw sewage as well as runoff
carrying fertilizers, pesticides, motor oil, and other
pollutants into nearby waterways. Runoff also results
in less water infiltrating through the soil to replenish
groundwater supplies. For a comparison of runoff
amounts from different types of landscapes, from
woods and meadows to urban business districts, see
page 42.
A sustainable home landscape is designed to keep
stormwater on the property, minimizing damage to
waterways and aquatic life.
The typical house has at least four downspouts, at each
corner of the house. Connecting rain barrels to one or more
of them not only captures water for irrigating the garden but
also helps minimize stormwater runoff.
On the pages that follow, you’ll find information
on stormwater management strategies such as
creating a rain garden, limiting impervious surfaces
in your landscape, and restoring vegetative buffers
along any wetlands and waterways adjacent to your property. You’ll also find a guide to green roofs. Collecting
rainwater that flows from your gutters not only provides an alternative to drinking water for irrigation but also
reduces stormwater runoff; see page 37 for details. It is important to use landscape materials that do not pollute
stormwater. For information on polluting materials and alternatives, see page 93.
41
Runoff Amounts From Different Landscapes
.6 inches of
runoff
.6 inches of
runoff
2.4 inches
of infiltration
2.4 inches
of infiltration
1 inch of
runoff
2 inches of
infiltration
1.6 inches of
runoff
1.4 inches of
infiltration
2.5 inches of
runoff
.5 inch of
infiltration
Impervious
surface 0%
Impervious
surface 0%
Impervious
surface 0%
Impervious
surface 38%
Impervious
surface 85%
Woods
Meadow
Row crop
agriculture
Residential
(0.25-acre lots)
Urban
business district
As development increases, so do soil compaction and impervious surfaces. Compacted soils, along with
driveways, roads, parking lots, rooftops, and other impervious surfaces, make it difficult for rain to infiltrate
into the soil, as in a natural setting. As a result, the more impervious surface in a landscape, the less infiltration
and the more stormwater runoff it generates. The illustration above shows the percentage of impervious
surface and the amount of infiltration and runoff following a 3-inch rainstorm for each kind of landscape.
42
create A Rain Garden
One of the most effective ways to prevent stormwater runoff in a home landscape is to create a rain garden.
Basically, a rain garden is just a strategically located low area where water can soak naturally into the soil. Like the
rest of your ornamental garden, it can be full of colorful plants.
Rain gardens have other benefits, too. They help protect your community from flooding. They protect local
streams and lakes from the many pollutants carried by stormwater as well as the physical damage it causes. By
increasing the amount of precipitation that filters naturally into the ground, they replenish underground water
supplies. And rain gardens also provide valuable habitat for birds, pollinators like butterflies and bees, and many
of the beneficial insects that help keep your garden healthy by keeping pest populations in check.
Following are some things to consider when planning a rain garden.
here to put it
•W
Locate your rain garden either near the house to catch only roof runoff, or farther away to collect stormwater
from the lawn as well as the roof. A rain garden can also capture precipitation flowing off of paved areas. Keep
it at least 10 feet from your house to prevent moisture problems.
ow big?
•H
A typical residential rain garden ranges from 100 to 300 square feet, but the time needed to dig the depression,
the cost of plants, and the size of your property will help determine how large yours should be. The size of a rain
garden that can manage most or all of your runoff also depends on what type of soil you have and how much
roof and/or surface area will drain into it.
ow deep?
•H
A rain garden should be 4 to 8 inches below the level of the surrounding land.
Rain gardens such as this one in Seattle can be attractive elements of your home landscape. They can also provide valuable
wildlife habitat, especially when native species are planted in drifts of three to seven of each for maximum impact.
43
hen the soil should be amended
•W
If your soil drains poorly, you may need to add a layer of sand or gravel at the bottom of your rain garden to
prevent it from becoming an ephemeral pond. If you have clay soil with enough rock or other aggregate, or you
have clay loam, the sand and gravel bottom is probably unnecessary, unless you want the water to drain very
quickly. If your soil is heavy clay, you may also need to amend it with sand and compost.
ow to connect it to a downspout
•H
To direct stormwater from a downspout, bury a length of plastic pipe in a shallow trench that slopes down to the
rain garden, or create a grassy swale.
hat to plant
•W
It’s helpful to think of a rain garden as comprised of three wetness zones: In the lowest zone, plant species that
can tolerate short periods of standing water as well as fluctuating water levels, because a rain garden will dry
grassy swale
porous soil
A rain garden should be 4 to 8 inches below the surrounding land. You can direct stormwater from a roof
downspout to the rain garden with a grassy swale, as above, or with buried plastic pipe. The soil in a rain
garden should be porous, so if you have heavy clay soil you may need to amend it with sand and compost. Rain
garden plants should be appropriate for your region and tolerate both wet and dry periods.
44
out during droughts or at times of year when precipitation is sparse. Species that can tolerate extremes of wet
soils and dry periods are also appropriate for the middle zone, which is slightly higher. Put plants that prefer
drier conditions at the highest zone or outer edge of your rain garden. To enhance the garden’s value as wildlife
habitat, plant native species in drifts of three to seven of each for maximum impact. After planting, apply a layer
of organic mulch 2 to 3 inches deep to keep down weeds and protect and enrich the soil.\
aintenance
•M
Although rain gardens require some initial effort, they are easy to maintain. Until your plants become
established, you’ll have to weed out undesirable volunteers. Leave the dormant plants standing over the winter
in cold climates to provide seeds and shelter for overwintering birds and butterflies. In spring you can cut back or
mow the stalks of herbaceous plants if you prefer a neat-and-trim look.
For More Information
Rain Gardens: A how-to manual for homeowners (http://learningstore.uwex.edu/assets/pdfs/GWQ037.pdf),
published by the Wisconsin Department of Natural Resources and the University of Wisconsin-Extension, contains
comprehensive, step-by-step instructions on all aspects of creating a rain garden “based on a goal of controlling
100 percent of the runoff for the average rainfall year while keeping the size of the rain garden reasonable.”
It includes a number of rain garden planting designs and plant lists for varying sun and soil conditions that are
especially appropriate for the Midwest.
An extensive list of plants (www.bbg.org/gardening/article/rain_gardens/rain_gardens_2) appropriate for rain
gardens and native to the eastern two-thirds of the U.S. and Canada, which was compiled by Temple University, is
available on the Brooklyn Botanic Garden website.
Your state or county Cooperative Extension office (www.csrees.usda.gov/Extension/) is also a good place to
seek information on rain gardens appropriate for your area. See the next page for some recommended Extension
publications.
Among the lovely native plants recommended for Pacific Northwest rain gardens are Nootka rose, left, and western
columbine, right.
45
“Adding a Rain Garden to Your Landscape” (www.umext.maine.edu/onlinepubs/PDFpubs/2702.pdf ),
University of Maine Cooperative Extension
“Rain Gardens” (www.csgc.ucsd.edu/BOOKSTORE/Resources/GS3%20Rain%20Gardens_8-10-09.pdf ),
Sea Grant California and University of California Cooperative Extension
“Backyard Rain Gardens” (www.bae.ncsu.edu/topic/raingarden/), North Carolina Cooperative Extension
“Rain Gardens” (www.water.rutgers.edu/Fact_Sheets/fs513.pdf), Rutgers University Cooperative Extension
“Rain Gardens” (www.sustainability.uconn.edu/pdf/raingardenbroch.pdf), University of Connecticut
Cooperative Extension
Rain Garden Handbook for Western Washington Homeowners (www.pierce.wsu.edu/Lid/raingarden/
Raingarden_handbook.pdf), Washington State University Extension Pierce County
For ideas on what to plant, you’ll find links to native plant societies of the U.S. and Canada here (http://www.
michbotclub.org/links/native_plant_society.htm). The Wildflower Center Native Plant Database (www.wildflower.
org/plants) is another helpful resource.
Limit Impervious Surfaces
Impervious surfaces are mainly constructed surfaces—rooftops, sidewalks, driveways, roads—covered by
impenetrable materials such as concrete, blacktop, and mortared brick or stone. But urban and suburban soils,
which are often compacted by intense foot traffic or construction equipment, are also highly impermeable. As
urbanization increases, so does the amount of impervious surface. Studies have shown that the pervasiveness of
impervious cover is directly related to the poor quality of many urban watersheds.
Because they prevent precipitation from seeping down into the soil, impervious surfaces are a primary cause of
stormwater runoff. Torrents of destructive runoff are generated as rainfall strikes rooftops and pours into gutters
and downspouts, picking up volume, speed, and pollutants as it rushes over paved surfaces and into storm drains.
What To Do:
Following are some of the ways you can reduce impervious surfaces to enable water to seep into the ground.
• Two ribbons of pavement with a low groundcover in between is a more porous alternative to a solid driveway of
concrete or blacktop.
• Use stepping stones surrounded by creeping groundcovers instead of continuous impermeable pathways.
• Opt for “dry laid” instead of “wet laid” or mortared patios and walkways. Set in stone dust or sand, these allow
some stormwater to infiltrate into the soil, unlike the impervious cement products typically used as mortar.
• Green spaces between patios, pathways, and other impermeable spaces can help prevent stormwater from
accumulating and running off your property. Plant a rain garden to capture stormwater runoff from your roof.
• Restore the structure of any compacted soil on your property, and take steps to prevent soil compaction
elsewhere in your landscape. See page 30 for details.
• Various types of permeable paving, such as concrete products with a porous structure that allows water to pass
directly through, can be expensive but are worth considering.
• Some green roof systems can help manage stormwater and are worth considering if you’re in the market for a
new roof.
46
A Guide To Green Roofs
Most green roofs currently being installed in North America are so-called extensive roofs that consist of four major
components: a waterproof and root-repellent membrane to keep water from leaking into the building, a drainage
system, 3 to 6 inches or less of lightweight growing medium, and vegetation that is adapted to the extreme
conditions on rooftops and requires little or no maintenance. Living roofs cost a lot more than conventional roofs,
but last about twice as long.
Green roofs help reduce the urban heat island effect—the difference in temperature between urban areas
and the surrounding countryside caused by the lack of vegetation and large number of paved and built
surfaces that absorb heat. Research (www.wildflower.org/greenroof/) at the Lady Bird Johnson Wildflower
Center shows that green roofs can be up to 80 degrees cooler than adjacent buildings with traditional roofs.
By insulating your home, they also can significantly reduce energy consumption and heating and cooling
bills. They filter pollutants, improving air quality in towns and cities. In urban areas especially, they can
provide valuable wildlife habitat (www.nwf.org/News-and-Magazines/National-Wildlife/Gardening/Archives/2007/
Green-Roofs-Take-Root.aspx). And they add aesthetically pleasing green space, reducing the monotony of
barren city skylines.
A green roof’s ability to manage stormwater runoff, however, has been debatable. The growing media used
on green roofs typically contain slow-release fertilizer, which can be carried away in excess stormwater runoff,
polluting local waterways and harming aquatic life. A 2009 study by the U.S. Environmental Protection
Agency comparing the quantity and quality of runoff from green and flat asphalt roofs concluded that green
roofs are capable of removing 50 percent of annual rainfall volume, although this varied seasonally from
about 95 percent in summer to less than 20 percent in winter. The study, which was conducted by the Penn
State Center for Green Roof Research, also concluded that green roof runoff did contain some nutrients, but
because the volume of runoff was reduced significantly, green roofs actually led to less nutrient pollution than
asphalt roofing. And the runoff can be directed from the roof to a rain garden, where the nutrients can help
nourish the plants.
The Wildflower Center found that some green roofs are better at reducing runoff than others. Researchers
compared the performance of six extensive green roof systems from six different manufacturers to each other
as well as to traditional non-reflective blacktop and somewhat cooler reflective white roofs at the Center’s
headquarters in Austin, Texas. Each roof was planted with the same 18 native species chosen for their wide
tolerance of both drought periods and saturation after rainstorms. The plants were provided with the same
amount of water for irrigation each week when rainfall wasn’t sufficient.
Compared to both conventional and reflective roofs, the green roofs were much better at preventing the
temperature of the inside air from spiking on warm days. Some of the roofs were able to capture a significant
amount of stormwater (80 percent of a half-inch rain event and 40 percent of 1-inch and 2-inch events),
but others were not significantly better in this respect than the white or blacktop roofs. What’s more, while
some of the roofs had nearly no adverse effect on water quality, others were worse than the typical suburban
lawn—the more fertilizer in the planting medium, the worse the water quality (and the faster the plant
growth), although water quality dramatically improved after the first growing season. In short, no one system
excelled at providing all the benefits often attributed to green roofs.
What To Do:
• Green roofs are substantial investments. Although they’re not space-age contraptions, building one isn’t simply a
matter of hauling potting soil and plants to your rooftop. It’s important to consult a landscape architect, engineer,
or roofing contractor with experience in green roof installation. A directory of accredited green roof professionals is
47
on the Green Roofs for Healthy Cities website (http://greenroofs.org/index.php?option=com_comprofiler&task=us
ersList&Itemid=&limitstart=0&search=&listid=4&name=&company=&city=Chicago&state=IL).
• Determine why you want a green roof—whether it’s aesthetic value, habitat value, or its ability to save energy or
retain stormwater. Make sure that a green roof is the most efficient way to achieve your goals.
• If you decide to pursue a green roof, make the consultant or manufacturer you are working with aware of your
goals and ask which green roof system is most likely to achieve them.
Protect And Restore Vegetated Buffers Along
Waterways And Wetlands
In undisturbed natural areas, waterways and wetlands are typically protected by adjacent vegetation. Grassland,
woodland, or wetland plant communities reduce runoff by increasing the land’s capacity to absorb stormwater.
Less runoff means less pollution of all kinds entering the water, including nutrients from fertilizers, pet wastes, and
other sources—excess nutrients are the primary cause of the algal blooms that rob oxygen from the water and kill
fish. Plant roots stabilize the soil and protect against erosion. The vegetation also improves wildlife and fish habitat
by providing food, shelter, and shade.
In many areas, however, the native vegetation has been removed and these important ecological functions have
been reduced or destroyed. In residential areas, turf grass often extends all the way down to the water, polluting it
with stormwater runoff carrying fertilizers and pesticides routinely used in lawn care.
In developed areas, vegetated buffers can fulfill the same important ecological functions as undisturbed waterside
vegetation. As the name suggests, these are thickly vegetated strips of land that protect waterways and wetlands
from polluted runoff and erosion. They also provide habitat for a variety of wildlife year round, including “stopover
habitat” for migrating birds in spring and fall.
Research shows that as the width of a vegetated buffer increases, its ecological benefits also grow. Buffers less
than 50 feet wide offer minimal protection, while those 200 to 300 feet in width improve water quality and protect
aquatic habitats. Vegetated buffers more than 300 feet wide can function as wildlife corridors and even harbor
imperiled and sensitive species.
What To Do:
• If your property borders a waterway or wetland, create a thickly vegetated and undisturbed buffer at least 50
feet wide. These riparian and coastal zones are often regulated, so contact local and regional government
agencies for information on appropriate vegetation buffers in your area.
• Do not use any pesticides or fertilizers—even organic fertilizers including compost—in a vegetated buffer area.
• Undisturbed buffers provide the best protection. If you need access to the water, create an elevated walkway
made from untreated wood to protect the vegetation as much as possible.
48
S ustai na b l e Wat e r Fe at u r e s
From decorative fountains and tubs to pre-formed
pools and ponds, water features have become
popular garden amenities, and for good reason.
The sight and sound of water is relaxing, and may
promote stress reduction and healing. Wetland
plants can be spectacular, whether the delicate
water-lilies that float on the still surfaces of ponds,
the brilliant cardinal flowers that populate marsh
edges, or the carnivorous pitcher plants that grow in
spongy bogs. The sound of a cascading waterfall,
a trickling stream, or even a bubbling urn adds
another dimension to a landscape and can drown out
unwanted clatter. What’s more, water features will
attract birds and other delightful wildlife to your yard.
Countless tomes on how to create a water feature
have been published in recent years, but they almost
never tell how to construct a feature that conserves
energy and potable water.
What To Do:
• Use alternatives to potable water, such as collected
rainwater or air-conditioning condensate, in your
water feature; see page 37 for details. Systems are
now available that combine a rainwater harvesting
and storage system with a decorative water
feature.
This sustainable water feature uses rainwater channeled from
the gutter. When rainfall is sparse it becomes a dry creek bed.
• Use solar recirculating pumps, which conserve water and are powered by a renewable source of energy.
• Consider using an ecological design approach, creating a water garden that includes plants appropriate for
local conditions and functions as a natural ecosystem. A streambed that goes dry for part of the year may be
appropriate in an arid area. An in-ground pond that mimics the natural zones of vegetation found in natural
ponds may be appropriate for a good-sized property in a high-rainfall area—complete with floating plants like
water-lilies in deep areas; pickerel weed, arrowheads, grasses and sedges that grow partially in water in the
emergent zone; and colorful wildflowers, shrubs, or trees found where the wetland grades into upland.
For More Information
The Natural Water Garden: Pools, Ponds, Marshes & Bogs for Backyards Everywhere(http://shop.bbg.org/mm5/
merchant.mvc?Screen=PROD&Store_Code=BGGS&Product_Code=BBG-NAT-151&Category_Code=BBG-NAT),
edited by C. Colston Burrell and published by Brooklyn Botanic Garden, takes an ecological design approach to
water gardening, with step-by-step instructions and recommended plants for the Northeast and Mid-Atlantic, the
Southeast and Deep South, South Florida, the Midwest and Great Plains, the Western Mountains and Pacific
Northwest, and California.
49
Plants
As wilderness shrinks and suburban acreage increases, what
we plant in our gardens is increasingly important. Much of the
remaining natural landscape has been overrun by invasive species
and fragmented by roads, subdivisions, and industrial complexes,
tattering the web of life that supports us. Even if we protected
every remaining natural area, there would not be adequate
habitat for many beleaguered plants and animals.
However, home gardens can mimic the complexity of
disappearing forests, prairies, and deserts and help support a
surprising number of species, including pollinators and songbirds.
Plantings suited to the conditions on our properties can also
conserve water, increase the energy efficiency of our homes, help
combat climate change, and enrich our lives with beauty.
In this section of the workbook, you’ll learn how to identify any
invasive plants in your landscape, and how to select plants
adapted to the conditions on your property. You’ll also find
information on growing native plants, landscaping for birds,
butterflies, and other wildlife, protecting your garden’s “biomass,”
greening your lawn, reducing the urban heat island effect, and
planting to increase your home’s energy efficiency.
Invasive non-native species like
Chinese wisteria cause more
than $138 billion of major
environmental damages a year.
Conventional And Sustainable Landscapes: How They Compare
Conventional Landscape
Sustainable Landscape
• Can include invasive plants that threaten natural
• Includes no invasive species
• Includes plants that are adapted to the
areas
conditions on the site
• Often requires water, fertilizer, and pesticides
• Often provides minimal habitat for wildlife
• Not designed to improve home energy efficiency
• Usually leads to higher water, heating, and cooling
• Includes plants chosen for beauty and wildlife
appeal
• Promotes home energy efficiency
• Can slash water, heating, and cooling bills
bills
50
I d e n ti f y a n d R emove Invas ive spec i es
o n Y o u r P r o p ert y
The U.S. government defines an invasive species as one that is not native to the ecosystem under consideration
and whose introduction causes or is likely to cause economic or environmental harm or harm to human health.
Studies have shown that at least half of the worst invasive plants—from purple loosestrife, jasmine, and glossy
privet to pampas grass—were brought here for horticultural use.
It’s a simple fact that two plants cannot occupy the same spot at the same time, so when an invasive non-native
plant escapes from a garden and settles into a new ecosystem, it displaces a native. Invasive plants may grow
faster, taller, or wider and shade out native species. Many stay green later into the season or leaf out earlier, giving
them an advantage over natives. They can reproduce quickly. The worst invasive plants can even alter important
natural processes like hydrology, fire, and nutrient flow—all with detrimental effects on native plants and animals.
The information below will help you identify any invasive plants in your landscape, and tell you the best ways to
remove them. You’ll also find tips on how to avoid planting an invasive species in the future.
What To Do:
• Make sure no invasive plants are growing in your garden.
Check the following websites, which include links to regional and state lists of invasive species as well as
information on individual plants:
Center for Plant Conservation (www.centerforplantconservation.org/invasives/links.html) links to state invasive
species lists and other information on invasive plants
USDA Natural Resources Conservation Service (http://plants.usda.gov/java/noxiousDriver#federal) includes lists
of federal and state invasive and noxious weeds
University of Montana-Missoula (http://invader.dbs.umt.edu/Noxious%5FWeeds/) includes a searchable database
of noxious weeds in the U.S. and Canada
• Remove any invasive plants currently in your landscape.
Techniques to rid your garden of these unwanted species range from benign “mechanical” methods to riskier
chemical herbicides. Use non-chemical methods whenever possible and herbicides as a last resort.
Hand-pulling is the most basic way to control unwanted plants. Pulling weeds by hand works best with small
herbaceous plants and small vines. Pull up the entire plant, roots and all, taking care to disturb the surrounding
soil as little as possible. Mulch the site afterward to suppress weeds. Be especially careful about disposing of
invasive plant material (www.beplantwise.org/guidelines/show.php?id=9) to prevent them from spreading.
It may also be possible to remove shrubs and small trees yourself, using pruners or loppers to remove the
branches, then digging out the stump. A variety of special tools such as the Weed Wrench are designed to make
removing woody plants easier. These are basically lever arms with a pincher at the bottom to grip the plant’s stem.
Once the stem is caught in the grip, you lean back and, after a little rocking, the entire plant comes up, roots
included. Consult an arborist for removal of large trees.
See the websites above for information on dealing with large infestations of invasive plants. If you must use herbicides,
your local Cooperative Extension (www.csrees.usda.gov/Extension/) office is a good resource for guidance on safe use
of the least toxic herbicides.
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• Avoid planting invasives in the future.
Many invasive plants are still being sold for garden
use, despite their documented ability to degrade
natural areas. And although no system is yet in place
to effectively screen them for potential invasiveness,
new plants from around the world are constantly
being introduced.
A foolproof system for predicting invasiveness so far
has proven elusive, but a few traits should raise red
flags. For example, nonnative species bearing fleshy
fruits dispersed by birds are at the top of the suspect
list. Declining to plant such species can help prevent
plant invasion. It’s also a good idea to avoid planting
any species you see escaping into vacant lots or
roadsides in your area, even if you cannot find them
on any official invasive species list.
Look for plants that have been growing in gardens
for decades without demonstrating any signs of
invasiveness. Whether native or non-native, these are
relatively safe to plant in your home landscape.
The most prudent prevention measure is to select
regionally native plants when possible. If you grow
In eastern states, Chinese silvergrass has escaped from
plants that are native to you region, it is highly
gardens and displaces native plants in old fields and along
roadsides and forest edges.
unlikely that you will be unleashing a new invasive
species in your area. And you will be preserving your
region’s natural character, including the complex
interrelationships between the native plants and the butterflies, birds, and myriad other creatures with which
they have coevolved. Native Alternatives to Invasive Plants (http://www.bbg.org/gardening/handbook/native_
alternatives/#/tabs-5), a Brooklyn Botanic Garden handbook, recommends a variety of beautiful, regionally native
trees, shrubs, vines, herbaceous plants, and grasses that satisfy the same garden needs as the worst non-native
invasive plants commonly used in horticulture, including size, shape, colorful flowers, or showy foliage.
For more tips on what you can do in your garden to prevent the spread of invasive species, see the PlantWise
(www.beplantwise.org/) website.
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Gr o w P l a n t s Adapted T o T he
C o n d i ti o n s I n Y o u r Ga r de n
Many new home gardeners make the mistake of choosing plants primarily on the basis of looks. In fact, almost
all gardeners do this at one time or another. We’re smitten by gorgeous plants at the nursery, then we’re faced
with the daunting task of creating the conditions they need, whether by modifying soil pH or structure or providing
regular irrigation. If we don’t make these modifications, the plants fail to thrive and often perish.
Aesthetic considerations are essential to creating a beautiful garden, but they’re not enough. For a thriving
garden, the plants must be matched to the growing conditions on the site, instead of vice versa. And when you
choose the right plants for your site, your landscape won’t be a never-ending maintenance headache.
Major Factors To Consider
Following are some of the major site conditions to keep in mind when you choose plants for your garden, whether
trees, shrubs, grasses, ferns, wildflowers, or heirloom annuals or perennials.
Hardiness Zone
Most plants available for sale at nurseries or through online suppliers have been assigned a hardiness zone that
correlates with a hardiness zone map. These are among the most basic tools gardeners have used for decades
to determine if a particular plant can survive winter in their area. Probably the best-known hardiness zone map
in the eastern two-thirds of the country was produced by the U.S. Department of Agriculture (USDA). The most
recent USDA map (www.usna.usda.gov/Hardzone/ushzmap.html), published in 1990, divides the country into 11
color-coded bands or zones. Each successive zone represents a 10 degree Fahrenheit difference in average annual
minimum temperature—the higher the number, the warmer the temperatures for gardening in that zone.
In 2006, using the same basic zone structure as the USDA, the National Arbor Day Foundation produced an
updated map (www.arborday.org/media/zones.cfm) for the U.S. based on more recent weather data.
Gardeners in the West generally use the system of 24 climate zones first published by the Sunset Publishing
Corporation in 1954 in the Western Garden Book. The Sunset zone maps (www.sunset.com/garden/climate-zones/
climate-zones-intro-us-map-00400000036421/) factor in not only minimum winter temperatures but also summer
highs, growing season length, humidity, and rainfall patterns.The zones correlate to a series of regional maps of
the West. Zone 1 represents the harshest growing conditions, zone 24 the mildest.
In 1997, Sunset published its first National Garden Book. Applying the same range of climatic criteria to areas
of the United States and Canada east of the Continental Divide, it added 21 new climate zones, zones 25 to 45.
Most gardeners in these regions, however, continue to use the USDA map.
It’s important to recognize that every garden is influenced by not only the regional climate but also microclimates.
These are areas that are warmer or colder, moister or drier than other parts of your landscape. All else being equal,
for example, planting beds on the south side of a house or garden wall will be considerably warmer than those on the
north wide. When purchasing plants, choose those that are best suited to any microclimates on your site.
Soil
What type of soil you have determines how well it drains and therefore its overall moisture level (see page 15).
If you have clay soil that drains relatively poorly, for example, you shouldn’t grow plants adapted to drier, leaner
53
conditions. Your soil’s pH will also help determine your plant palette. For more information on what to plant in
particular soil conditions, see “Problem Soils,” page 28.
Water
If you live in Los Angeles where rainfall averages 15 inches a year and comes mostly in the winter months, the
plants adapted to your natural precipitation patterns are different from those in New York City, which receives
about 45 inches of rain a year, more evenly distributed from month to month.
Keep in mind that soil moisture conditions can vary in your yard, and you need to plant accordingly. A southfacing slope, for example, is likely to be drier than a low, shady spot.
Plants themselves often provide clues about their water needs. For example, manzanitas and other shrubs of the
coastal sage scrub, the dominant native plant community in Los Angeles, tend to have thick, leathery, evergreen
leaves good at conserving water. Plants with silvery, hairy, or fuzzy leaves (such as woolly thyme), succulent leaves
(such as portulaca or rose moss), or leaves with a waxy coating (such as ivy-leaved geranium) typically have low
water requirements.
Sun and Shade
Plants need sunlight to photosynthesize and make their food, and only some can tolerate low light levels.
Conversely, those that have evolved for shady conditions will often burn up if planted in full sun. If you look
at plant labels, nursery catalogs, or gardening books you’ll see that the needs of many plants are commonly
expressed in degrees of sun or shade:
Full sun: means 6 to 8 hours of direct sunlight a day.
Partial sun or light shade: generally refers to an area that gets bright to full sun for all but a few hours of
the day.
Partial or medium shade: an area that gets bright light or sunshine for roughly half of the day and shade for
the other half.
Full shade: means the sun is obstructed for most of the day.
Dense shade: is near-total shade, which is too dark for healthy plant growth except for the most shadetolerant species.
Most plants described as shade-loving fall in the middle ranges. If you have morning sun and afternoon shade,
most of the plants described as “good for shade” will grow well for you. In these brighter shady conditions, plants
labeled shade-tolerant produce a good flush of foliage and the best flowering display. If you have morning shade
and intense afternoon sun, however, the same plants may look stressed or burned, particularly in hotter climates.
Plant Labels
If you’re plant shopping at the local garden center, plant labels, whether stickers, plastic inserts, or paper tags, are
the place to start looking for information on whether particular specimens are suited to the growing conditions in
the spots you’d like to put them. Labels are a good general guide to plant needs.
Among the wealth of information on a typical label are the plant’s common and Latin names, its hardiness zone,
when it blooms (if it’s a flowering plant), and its light and moisture requirements. It usually tells you how tall and
wide the plant will grow, and how far apart you need to plant if you’re growing more than one specimen. It may
even indicate whether the plant performs best in acidic, alkaline, or neutral soil.
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For More Information
Labels are the place to start, but it makes sense to look further. Ask professional horticulturists at local public
gardens or nurseries to recommend plants that suit your garden’s conditions. Plant catalogs and regional
gardening books are other good resources. Your county Cooperative Extension (http://www.csrees.usda.gov/
Extension/) office probably publishes lists of recommended plants for your area.Be aware, however, that these
sources may recommend a plant that is invasive in your area, so check regional lists of invasive species before
buying.
State and local native plant societies are great sources of information on native trees, shrubs, and wildflowers
(www.michbotclub.org/links/native_plant_society.htm) that will thrive in your garden. You can also search the
Native Plant Database (http://www.wildflower.org/plants/) on the Wildflower Center website to find information on
more than 7,000 plants native to North America.
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G r o w N ati v e P l ant s
Who hasn’t admired the expanses of bluebonnets and
bright orange Indian paintbrushes that bloom along
Texas roadsides, or the way the eastern deciduous
forests explode into a fireball of foliage color in
the fall? Yet across this continent of breathtaking
natural beauty most of us have planted a few dozen
ornamental plants from China, Europe, and other
places around the world.
About 20,000 plant species are native to the United
States, growing in an amazing range of habitats,
from the tropical rain forests of Hawaii to the deserts
of Arizona. Unfortunately, these natives, the species
that existed in various regions without human
introduction, are disappearing at an alarming rate.
Botanists are concerned about the survival of one in
every five of this country’s native plants—and these
plants provide critical habitat for countless other
creatures. Fortunately, many native plants can play
leading roles in our home landscapes.
Why Grow Native?
Native wildflowers can add beauty to your garden,
just as they do in natural landscapes. The great
variety of plants native to any region give gardeners
options that work well in any type of garden design.
But native plants also do much more.
Alpine aster is found in the Rocky Mountains and Pacific
Northwest.
• Plants native to your region are adapted to your climate and other conditions. When you select native plants
that match the conditions on your property, it’s not necessary to modify your soil to have a thriving garden.
And once established they don’t require regular watering, fertilizing, and coddling with pesticides the way many
commonly grown nonnative plants do. This means less work for you and less money spent on water, fertilizer,
herbicides, and insecticides.
• Native plants are the foundation of the biodiversity that maintains our own life support systems. For example,
they nurture important pollinators like bees, butterflies, and hummingbirds.
• Native plants are less likely to escape the garden and become invasive. By choosing native plants, you avoid
planting invasive non-native species that threaten remaining natural areas.
• Native plants create a distinctive sense of place, preserving the natural character that has inspired artists and
poets and created the traditional culture of your region.
How To Start Growing Native
Growing natives can be as simple as adding a regionally native shrub or wildflower to an existing flowerbed or
border, or planting native trees that will make your home more energy efficient by providing summer shade or
56
blocking winter winds. It can mean protecting and restoring an area of native habitat—a fragment of prairie
or forest, for example—already on your property, adding appropriate native plants to restore its diversity and
complexity. You can also create a native planting from scratch by re-creating the native habitat that once existed
on your site. Even a tiny yard can include a patch of meadow or a woodland glade. You can even enhance your
landscape’s diversity by adding habitats that did not exist on the site but are found in the area and make the most
of the new conditions that have been created by human development—for example, a rain garden full of lovely
local wetland plants, supported by stormwater runoff from your roof.
Here are some basic native gardening tips:
• The best way to get started is to become familiar with the native plant communities in your region and the trees,
shrubs, flowers, and other species that grow there. See “What’s Your Ecoregion?” on page 58.
• When selecting native (like any other) plants to add to your landscape, choose species that are appropriate for
the particular soil, light, and other conditions in the place you want to put them.
• When designing a native garden, it’s a good idea to use a local plant community as a model. Again, the basics
of the site—soil type, topography, and microclimate—will determine which communities are appropriate.
Often, more than one native plant community will be appropriate on any given site. Functional considerations—for
example, the need to screen out an eyesore in a neighbor’s yard—will usually narrow down the choice, in this case
favoring a woodland or tall shrub community over a meadow or prairie.
• A good way to begin designing a native planting is to study the key species that occur together in the chosen
plant community in the wild. First, note what the dominant species are—the major plants that form the
This Massachusetts woodland garden includes an array of beautiful trees, shrubs, herbaceous wildflowers, and ferns native
to New England. An inviting path meanders through the landscape.
57
backbone of the plant community. In the tallgrass
prairie, these are the grasses such as stately big
bluestem, which can reach 6 feet in autumn. In
the pinyon-juniper woodlands of the Southwest,
the major plants are the species of juniper and
pinyon pine, which vary somewhat from state
to state. In the coastal forests of the Pacific
Northwest, conifers, including redwood and
Douglas fir, dominate.
• Next, note which plants form the various vertical
layers in the plant community. A woodland
garden, for example, can include all the vertical
layers found in a surrounding native forest,
including tall canopy trees, smaller understory
trees, and shrubs, as well as herbaceous
wildflowers and ferns.
• Another design consideration in a native planting,
like any beautiful garden, is seasonal change.
Note the annual succession of bloom in the plant
community. A spring meadow of pink and purple
wildflowers may change to yellows and greens
in summer, then shades of purple and gold in
fall. To have seasonal complexity—and provide
a continuous supply of food for wildlife—a native
garden needs a variety of plants that flower at
different times.
Harlequin blueflag is a lovely native of northeastern states.
• Most people think a native garden must be
naturalistic, not formal in design, because nature doesn’t line things up in straight rows or plant them in
geometric shapes. But native gardens function equally well for people and wildlife whether the plants are
planted in formal or naturalistic arrangements. If you want a naturalistic garden, observe the way horizontal
masses of plants form soft shapes, the way forest paths flow in gentle curves, or the way deserts are etched by
arroyos. Also note how some plants in nature are present only as individuals, others in loose colonies or dense
clumps.
• There’s plenty of room for artistic expression in a native garden, as in any garden. As noted above, there’s
often a choice of plant community models suited to a particular site. And in nature, no two patches of plant
community are exactly alike. There is a choice of species, particularly non-dominant ones, to feature in your
native garden. They can be chosen for their habit or form, seasonal color, interesting bark, and eye-catching
contrast—just as in a traditional garden.
• Because some native wildflowers, such as woodland orchids and trilliums, are difficult to propagate, they are
sometimes dug up from the wild and sold, endangering local populations. Question your suppliers carefully about
the origins of the plants you want to buy. Make sure they were nursery propagated, not collected from the wild.
Maintaining a Native Garden
Native gardens, like all new landscapes, need some investment of time and energy during the first year or so. In
a woodland garden, for example, young trees, shrubs, and herbaceous plants may need to be watered until they
become established if there isn’t enough rain. Mulching will retain moisture and discourage weeds, but after a
few years your patch of prairie or forest should be producing most of its own mulch as its sheds its leaves. Periodic
58
weeding, mowing, or (where legal) controlled burning of prairie and meadow gardens will be necessary to control
non-native weeds and discourage woody vegetation.
Eventually, your native garden should be fairly self-sufficient. Natural processes can be left to take their course—
leaves to remain on the ground, volunteer seedlings to spring up. In fact, part of the pleasure of a native garden is
watching the web of life unfold.
For More Information
The Wildflower Center website (www.wildflower.org/howto/show.php?id=23&frontpage=true) includes lots of
information on growing native plants and designing native gardens.
Native plant societies are also excellent sources of information on native plants for gardens. You can find a list of
them here. (www.michbotclub.org/links/native_plant_society.htm)
Wild Ones (www.for-wild.org/) is a nationwide group of gardeners who promote landscaping with native plants.
State chapters (www.for-wild.org/chapters.html) offer opportunities to get together with others interested in native
plants and natural landscaping.
Brooklyn Botanic Garden has published several inexpensive yet information-packed handbooks on gardening with
native plants, including:
Going Native: Biodiversity in Our Own Backyards (http://shop.bbg.org/mm5/merchant.
mvc?Screen=PROD&Store_Code=BGGS&Product_Code=BBG-NAT-140&Category_Code=BBG-NAT), edited by
Janet Marinelli
Wildflower Gardens (http://shop.bbg.org/mm5/merchant.mvc?Screen=PROD&Store_Code=BGGS&Product_
Code=BBG-NAT-159&Category_Code=BBG-NAT), edited by C. Colston Burrell
Native Perennials: North American Beauties (http://shop.bbg.org/mm5/merchant.mvc?Screen=PROD&Store_
Code=BGGS&Product_Code=BBG-PLA-146&Category_Code=BBG-STO), edited by Nancy Beaubaire
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Major Ecoregions Of The Continental U.S.
The earth’s natural vegetation is divided into large areas of forest, shrubland, grassland, and desert called
ecoregions, biomes, or vegetation associations. Find your ecoregion on the map on below, and learn more about
it in the pages that follow.
Terrestrial biomes in North America
Tropical & Subtropical Coniferous Forests
Temperate Broadleaf & Mixed Forests
Temperate Conifer Forests
Mediterranean Forests, Woodlands & Scrub
Deserts
Temperate Grasslands, Savannas & Shrublands
Boreal Forests & Taiga
Tropical & Subtropical Grasslands, Savannas & Shrublands
Flooded Grasslands & Savannas
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The major ecoregions of the continental U.S. include:
Temperate broadleaf and mixed forests
Found from Maine to Minnesota and southward to northern Georgia and Louisiana, this biome includes the
vast broadleaf deciduous forest that predominates in much of the East. The deciduous forest is actually many
forest associations with different dominant species, such as sugar maple, American beech, basswood, oaks, and
hickories. In some areas, like the northern reaches of the ecoregion, conifers form mixed associations with the
deciduous trees.
Temperate conifer forests
Several major coniferous forests are found in the U.S. Pine-dominated forests cover extensive areas of the
Southeast in a wide swath along the Atlantic and Gulf coasts. The Rocky Mountains, Sierra Nevada, and
Cascades are blanketed with dense forests of mixed conifers. Distinct associations of species are found in these
areas, but they share trees such as Douglas fir and lodgepole pine. Magnificent species such as California’s
redwoods and giant sequoias are found along the Pacific coast.
Temperate grasslands, savannas, and shrublands
The midsection of the country, from the Canadian border south into Texas, is dominated by grasslands that are
commonly known as prairies. Although it is now largely farmland, the mid-continent was once a vast grassland
because factors like relatively little rain and the influence of fire made the growth of woody plants difficult. Where
the prairie met the forest, open, parklike areas called savannas were found. In savannas, now mostly gone, small
expanses of prairie were interspersed with open groves of trees sheltering shrubs and woodland wildflowers.
Grasslands like this one in Missouri once dominated the midsection of the U.S., from the Canadian border south into Texas.
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Deserts
North America’s four desert associations—the Great Basin, Mojave Desert, Sonoran Desert, and Chihuahuan
Desert—are situated between two enormous mountain ranges, the Sierras and the Rockies. The Great Basin is
a cold-desert region encompassing most of Utah and Nevada and parts of adjacent states in which most of the
sparse precipitation falls as snow. The three warmer deserts to the south receive their annual precipitation as rain,
either in winter or summer.
Mediterranean forests, woodlands, and scrub
This ecoregion is composed of California’s coastal ranges as well as the western slopes of the Sierra. It’s
distinguished by a Mediterranean climate with warm, dry summers and cool, moist winters. Coastal sage scrub
and chaparral, both dominated by shrubs and small trees, interspersed with grasslands and oak woodlands, are
the major plant associations of this relatively arid biome which receives 15 to 25 inches of rainfall a year.
A few smaller biomes are also found in the continental U.S. Tropical and subtropical grasslands, savannas, and
shrublands ring the Gulf coast of Louisiana and Texas, for example, while savannas and flooded grasslands,
commonly known as the Everglades, can be found in South Florida.
Each of these major biomes is a plant community on a grand scale, yet each also has many smaller plant
communities within its borders. For instance, the easternmost portion of the grassland biome of the central U.S.,
with deep, rich soils and ample rainfall for luxuriant growth, supports tallgrass prairie. Farther west, where rainfall
is more moderate, typically less than 20 inches per year, mixed-grass prairie grows, while shortgrass prairie is
found in the rain shadow of the Rocky Mountains, where the annual rainfall of 15 inches or less is scarcely more
than that in a desert.
All of these plant communities, large and small, are determined by soil type, topography, available water, and
extremes of temperature—the same factors that need to be taken into account to create a regionally appropriate
garden. They are your guide to what sorts of plants will grow best in your garden.
Your state native plant society is a great source of information on your region’s plant communities and plants to
grow in a native garden. You can find a list of native plant societies here (www.michbotclub.org/links/native_
plant_society.htm).
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L a n d s c a p e F o r Wildlife
As wilderness disappears and the human-dominated landscape grows, butterflies, songbirds, and other creatures
are left without places to live. Douglas Tallamy, University of Delaware entomologist and author of Bringing
Nature Home (http://bringingnaturehome.net/native-gardening/gardening-for-life), has pointed out that we have
already turned 54 percent of the lower 48 states into cities and suburbs, and 41 percent more into various forms
of agriculture. In other words, we humans have already taken 95 percent of the original native habitat.
And quality wildlife habitat continues to dwindle at a rapid rate. New development eats up 2 million additional
acres each year—an amount equal to the size of Yellowstone National Park. Invasive plants from our gardens run
rampant in the remaining natural habitats and replace the native plants upon which wildlife depend. The overuse
of chemical pesticides can poison the few food sources that do exist.
Meanwhile, years of research by evolutionary biologists have shown that the area required to sustain biodiversity is
pretty much the same as the area required to generate it in the first place. This means that since we have taken 95
percent of the country from wildlife, we can expect to lose 95 percent of the species that once lived here. In March
Since space is limited in most home gardens, it makes sense to plant the natives that support the most wildlife.
Native oaks ranked best in one study, providing habitat for more than 517 butterflies and moths alone. The
trees also provide food and shelter for many birds and mammals.
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2009, the Department of the Interior released a report (www.stateofthebirds.org/2009/) on bird populations in the
U.S. showing that nearly a third of the nation’s bird species are already endangered, threatened, or in significant
decline. The report called the troubling decline of bird populations during the past 40 years “a warning signal of the
failing health of our ecosystems.”
What To Do
The good news is that although many plants and animals have already disappeared from local and regional
landscapes, total extinction does not happen immediately. We still have time to save much of the biodiversity that still
exists if we start sharing our home landscapes with the plants and animals with which we humans have co-evolved.
• To make your garden a home for wildlife, you need to provide a few essentials:
Food
This means growing native plants—lots of them. For the vast majority of native wildlife, most of the non-native
plants we’ve favored in our landscapes for more than a century do not provide sufficient food, including the insects
on which 96 percent of all terrestrial birds depend. But when you plant native trees, shrubs, and herbaceous
plants, you provide wildlife with the nectar, pollen, fruits, leaves, seeds, and nuts—and associated insects—that
have nourished them for millennia.
Space is limited in the typical home garden, so it makes sense to plant the natives that are the champions at
providing food and shelter for birds and other wildlife. According to a study by Tallamy, native oaks support 517
species of butterflies and moths alone. They were the woody plants ranked best at supporting these insects that
are a crucial part of the diet of many animals, followed by native willows (456 species), cherries and plums (448
species), birches (413 species), poplars and cottonwoods (368 species), crabapples (311 species), blueberries
and cranberries (288 species), maples and box elder (285 species), elms (213 species), pines (203 species), and
New studies show that native plants provide substantially more food for wildlife than conventional landscape plants do—
one of the most important reasons to grow as many natives as possible in your garden. Above, a Monarch sips nectar from
a purple coneflower.
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hickories (200 species). You can find Tallamy’s lists of the best woody and herbaceous plants for wildlife here
(http://bringingnaturehome.net/native-gardening/gardening-for-life).
Water
Like all living things, wildlife needs water for drinking as well as bathing and cooling off. And like people, many
birds and other animals seem to simply like being around water.
Water can be a scarce commodity in arid areas and in cities. Nature provides water to wildlife in a multitude of
ways that you can replicate in your home landscape. In moderate or high-rainfall areas, an in-ground pool or pond
may be appropriate, and many recent books provide instructions on how to create them. Even a water garden in a
half-barrel planter or other large container will attract good-size birds and a variety of fascinating insects. Although
birds may drink from such sizable water features, they are too deep for bathing. For this purpose birds prefer either
a natural puddle or its manmade equivalent—a birdbath. Misters will attract hummingbirds, and damp open spots
will provide many butterflies with a place to drink and ingest minute amounts of nutrients from the soil.
Places to hide, rest, and nest
Native trees, shrubs, thickets, and grasses, brush piles, and manmade wildlife houses serve these important
purposes. All trees and shrubs provide cover, but none are better than evergreens, especially conifers, when birds
need to beat a quick retreat. And the seeds in their cones are an important source of food for some species. As
with other plants for wildlife, regionally native pines and other conifers are best, since they are more likely to host
the native insects upon which birds depend. At least 48 species of birds are known to use the eastern white pine
alone for feeding, cover, and nesting.
• To provide the most habitat niches for the widest array of wildlife, it helps to recreate the various vertical layers
of vegetation found in nearby natural areas. See Protect and Restore Your Landscape’s Vegetation for details.
• Don’t use pesticides. Even Bt (Bacillus thuringiensis), which is promoted as a safe and natural insecticide, kills
butterfly and moth caterpillars. Some pesticides can harm birds and other wildlife directly, and others can
contaminate the insects and flower nectar that they eat.
For More Information
The National Wildlife Federation website (www.nwf.org/Get-Outside/Outdoor-Activities/Garden-for-Wildlife/
Create-a-Habitat.aspx?CFID=18609613&CFTOKEN=d86a6085893c9dc0-A0883BCC-5056-A84BC3B9697BB7961A26) includes information on how to provide essential elements for a healthy and sustainable
wildlife habitat. There are also instructions on how to join the thousands of wildlife enthusiasts who have had their
backyard habitats certified by the organization.
The Wildflower Center website (www.wildflower.org) includes lots of information on landscaping for wildlife,
including links to other sources.
The Wildlife Gardener’s Guide (http://shop.bbg.org/mm5/merchant.mvc?Screen=PROD&Store_
Code=BGGS&Product_Code=BBG-NAT-372&Category_Code=BBG-DES), by Janet Marinelli, published by
Brooklyn Botanic Garden, recommends 10 specific projects and provides countless tips that will make your garden
a refuge for wild creatures. It also contains lists of native plants for regions across the U.S. with proven appeal for
birds, butterflies, bees, bats, hummingbirds, moths, and other wildlife.
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P r o t e c t a n d Re store Your
L a n d s c a p e’ s V e ge tat io n
The sum total of your garden’s vegetation, from the smallest fern to the tallest tree, is technically known as its
biomass. Producing and maintaining biomass is one of most important functions of a natural ecosystem or a home
landscape. It begins with photosynthesis, as plants use the sun’s energy to transform water and carbon dioxide from
the atmosphere into the food that they and all animals, including us, need to survive.
When land is developed, its natural vegetation is typically removed. Even when the native plant communities are
replaced with residential gardens, the site’s original biomass is often drastically reduced. When we decrease a
landscape’s biomass, we diminish its ability to provide natural benefits, from absorbing stormwater to cooling our
towns and cities.
Home gardeners can begin to restore the landscape’s biomass. One way to do this is to minimize the paving and
maximize the vegetation in your garden. Another is to design your plantings so that they include the various vertical
layers that were present in the site’s original natural landscape.
Vertical Layers Of A Woodland And Prairie Garden
Like a native forest, a woodland garden, left, can have four aboveground layers of vegetation: a canopy of
the tallest trees, an understory of smaller flowering trees, shrubs, and a ground layer of herbaceous plants
including ferns and wildflowers. Like their wild counterparts, prairie gardens, right, can also include several
vertical layers, including grasses and wildflowers of different heights. All plant communities also have
underground layers. In a prairie, the underground layers range from fibrous-rooted grasses to wildflowers with
deep taproots.
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Vertical Layers of Growth
All native plant communities consist of various vertical layers. These vertical layers are most obvious in forested
regions. The tallest layer of a forest is called the canopy and is composed of mature trees. The highest canopy
trees may be 100 feet or more, while the lowest grow to about 30 feet.
The next layer down is called the understory. It is composed of saplings of canopy tree species as well as smaller
flowering trees such as dogwoods and redbud. The understory layer extends from about 12 to 30 feet above the
ground.
The shrub layer is the lowest layer of woody vegetation. It occupies the area between 3 and 12 feet.
The lowest aboveground layer of a forest, below 3 feet, is called the ground layer. Here, wildflowers, ferns, grasses,
and sedges grow in often spectacular combinations. Plants in the ground layer also partition their environment
vertically. Spring ephemeral wildflowers bloom first, typically raising their foliage only a few inches above the leaf
litter. As they go dormant, taller ferns and wildflowers overtop them.
Deciduous forests have the most elaborate vertical structure, as described above. Coniferous forests, with their
dense stands of evergreen trees, typically have very little understory, but can have a dense shrub layer and ground
layer of wildflowers and mosses. Pine forests have the most open canopies of the coniferous forests, with scattered
understory trees and a well-defined shrub layer. Ground-layer plants are scattered in the sunny openings.
Native plant communities dominated by shrubs, such California’s chaparral and sage scrub, have mixed layers of
different-sized shrubs, with a ground layer of herbs, grasses, and sedges.
Prairies and other communities dominated by herbaceous plants also have distinct vertical layers. The earliest
plants to emerge in spring are low to the ground. Each successive emerging plant overtops the next, culminating
with the tallest grasses and late-blooming asters and other composites that end the growing season. The layers
also extend below the ground, from fibrous-rooted grasses to wildflowers with deep taproots.
In general, the more vertical layers there are, the more diverse the plant life, and therefore the more habitat
created for a wider array of animal life.
What To Do
• To restore biomass, consider ways to replace paved areas with plantings. This yields other benefits as well. The
extra planting beds help reduce stormwater runoff, for example. For ideas on how to reduce paved areas, see page
46.
• Re-create the layers of plant growth found in local native plant communities. Restoring the missing vertical
layers does more than boost your landscape’s biomass. It can also serve various aesthetic purposes. In forested
regions, for example, home landscapes usually consist mostly of lawn, dotted with a few shade trees. As they
do in forests, the tall trees lend a grand vertical scale to the garden, creating a cathedral-like enclosure. Adding
understory trees provides a more intimate, human-scale “ceiling.” Shrubs can become “walls” that divide spaces
horizontally or fill in a woodland border to create privacy. Beautiful tapestries of wildflowers and ferns create a
much more diverse and interesting ground layer than large expanses of lawn.
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G r e e n Y o u r L aw n
According to the Lawn Institute, there are an estimated 46.5 million acres of turfgrass in the United States—an area
greater than the states of Pennsylvania, Delaware, and Rhode Island combined. The vast majority of home lawns
consist of thirsty turfgrasses that originated in parts of Eurasia that get a lot more rainfall than much of the U.S.
Nationally, homeowners spend $6.4 billion a year to coddle these out-of-place plants. In their book Redesigning
the American Lawn, F. Herbert Bormann, Diana Balmori, and Gordon T. Geballe note that we spend as much
as $5.25 billion on fertilizers derived from fossil fuels, and an additional $700 million on the poisons used to kill
turfgrass pests. Lawn accounts for a big chunk of the typical water bill, too. It’s estimated that the typical suburban
lawn guzzles 10,000 gallons of water each year above and beyond that supplied naturally by rainfall. Ten percent
of the country’s air pollution is generated by lawn and garden equipment, says the Environmental Protection
Agency, and gasoline spills from refueling lawn mowers, edgers, and the like add up to some 17 million gallons a
year—far more than the 10.8 million gallons of crude oil spilled into Alaska’s Prince William Sound in 1989 by the
Exxon Valdez.
What To Do
• Because the typical approach to the American lawn requires more water and fertilizer than other parts of the
garden and mowing consumes energy and results in pollution, it’s best to cut it down to size or drastically
change the way you approach your turf. Replace all or part of your traditional high-input lawn with more
sustainable alternatives.
• If you need a lawn in your landscape, grow turfgrass that is appropriate for your area. In the past couple of
decades, low- and no-mow grasses, many of them native to North America, have been developed for various
climate regions. Unlike conventional lawns, they don’t require constant watering, feeding, mowing, and weeding
(or worse, herbicides), so in addition to being better for the environment, they’re less work for you. The following
are among the most popular and readily available.
Buffalograss
One example of a native grass now grown as lawn—a great success story—is buffalograss. Native to the Great
Plains, from Minnesota to Montana and south into Mexico, it grows wherever conditions aren’t too moist, too
sandy, or too shady. It can handle -30 degrees Fahrenheit and high heat. It has a fine, soft texture and is slow
growing, typically reaching a height of about 6 inches. It needs mowing only rarely if at all. Unlike most nonnative
turfgrasses, buffalograss needs minimal water once established and no fertilizer. Buffalograss cultivars have now
been developed that can be grown in suitable conditions in the eastern two-thirds of the U.S., as well as California.
In the Golden State, for example, irrigation and horticultural professionals have launched the Grass Roots
Program, an effort to wean residents from water-hogging Bermuda grass and fescues, which currently comprise 99
percent of California’s lawns. These traditional turfgrasses soak up 40 to 50 percent of the state’s potable water,
and 7 percent of its energy is consumed to transport this water to consumers. As an alternative, the Grass Roots
Program is promoting UC Verde, a buffalograss cultivar developed in California for the state’s climates that rates
twice as high as other turfgrasses for drought tolerance and reduced water use, pest and disease resistance, and
density. In fact, UC Verde requires 80 percent less water than tall fescue and 40 percent less water than Bermuda
grass—no small consideration in an arid state that in recent years has suffered repeated droughts. What’s more,
it grows slowly, to 4 to 6 inches tall, and no set cutting schedule is necessary. Even for neatnicks wedded to the
manicured look, mowing once a month is sufficient. More information on California’s Grass Roots Program is
here. (www.grassrootsprogram.com/)
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Blue grama
In very dry areas of the country, buffalograss is
sometimes mixed with the even more drought-tolerant
blue grama to insure solid green color throughout
the dry season. Native throughout the Southwest and
Great Plains regions, blue grama is a fine-textured
grass that typically grows 8 to 12 inches tall.
Fine fescues
In roughly the northern third of the country and in
southern Canada, mixes of low-growing fine fescues
are a good alternative to conventional turfgrasses.
They require mowing only once or twice a year—if
that—need little if any irrigation once established, and
thrive in full sun to partial shade.
Contact your county Cooperative Extension office
(www.csrees.usda.gov/Extension/) for more information
on which alternative turfgrass varieties are best suited
for your area.
• Fertilize sparingly and less frequently. Too much
Conventional lawns take a huge toll on the environment. A more
sustainable approach is to downsize your lawn and grow one of
the new low- or no-mow turfgrasses native to North America.
fertilizer can run off into nearby waters, leach into
groundwater, or lead to weed problems. With less
fertilizer, your lawn will grow more slowly and require less mowing, further reducing your lawn’s environmental
footprint.
• When mowing is required, use a mulching mower, and leave the clippings on the lawn. This not only minimizes
the energy consumed to transport the clippings to the local landfill, but also reduces the need for nitrogen
fertilizers.
Ground covers
Most people appreciate the fact that lawn provides some open space around their homes. But scores of beautiful
ground covers can play this role with a far smaller environmental footprint.
Some ground covers are invasive, including vinca and English ivy, which multiply rapidly in forests of the East and
Northwest. Make sure any ground covers you use are not invasive in your area.
To reduce the amount of lawn in your landscape, consider planting native plant gardens to provide food and
other benefits for pollinators and other wildlife. There are lovely native ground covers for every region. A favorite
combination of many eastern woodland gardeners, for example, is creeping phlox and foam flower. In spring,
the dense, eight-inch-tall spikes of pale to deep purple flowers of the phlox mingle with the foam flower’s small,
creamy-white flowers on upright stems. Check the Wildflower Center website (www.wildflower.org/howto/show.
php?id=23&frontpage=true) for ground covers native to your region. Or check with your state’s native plant
society (www.michbotclub.org/links/native_plant_society.htm).
Decks and patios
Lawns are often considered essential outdoor living space, but decks and patios fill the same function and require
a lot less maintenance. Be sure to build them with the most sustainable materials available.
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For More Information
The Wildflower Center website includes a number of articles on growing native lawns. See, for example:
Native Lawns
(www.wildflower.org/howto/show.php?id=11&frontpage=true)
Native Lawns: Buffalograss
(www.wildflower.org/howto/show.php?id=19&frontpage=true)
Easy Lawns: Low Maintenance Native Grasses for Gardeners Everywhere (http://shop.bbg.org/mm5/merchant.
mvc?Screen=PROD&Store_Code=BGGS&Product_Code=BBG-TEC-0160&Category_Code=BBG-TEC), a
Brooklyn Botanic Garden handbook edited by Stevie Daniels that includes information on scores of native grasses
suitable for growing as lawn across North America.
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L a n d s c a p e to i nc re ase you r Ho m e ’s
E n e r g y E f f i c i en c y
Collectively, houses use 22 percent of the energy
consumed in the United States today. About half of
this is for heating and cooling. A properly designed
landscape can make your home significantly more energy
efficient and in the process reduce air pollution, including
greenhouse gases. It can also slash your heating and
cooling bills by as much as 40 percent.
An energy-conserving landscape utilizes trees, shrubs,
groundcovers, and vines to provide cooling summer
shade as well as insulation against heat loss in winter.
It can perform aesthetic functions at the same time. A
windbreak, for example, can define the space in your yard
or patio and provide privacy while blocking blustery winds.
And by using plants as living air conditioners or insulating
blankets, you can soften your house’s architectural edges
with foliage and flowers while improving its performance.
Which Climate Region Do
You Live In?
Where you live helps determine the best energyconserving landscape strategies. Various climate
classification systems have been developed, but for the
purposes of energy-conserving landscaping, a simple
scheme that divides the U.S. into four climate regions—
cool, temperate, hot and arid, and hot and humid—is
sufficient. The cool zone includes the northern Plains and
Trees can reduce summer temperatures significantly
Midwestern states and the northern tip of New England.
when located on the south and west sides of your home.
The temperate zone is a wide swath extending from the
Deciduous trees provide summer shade and drop their
Pacific Northwest across the continent to southern New
leaves in fall, allowing the winter sun to warm the house.
England and the mid-Atlantic states. The hot and arid zone
more or less conforms to what is popularly known as the
Desert Southwest, including southern California, and the hot and humid zone runs from south-central Texas east to
Virginia and Florida.
The U.S. Department of Energy recommends the following landscaping strategies for each region, listed in order of
importance:
Cool
• Use windbreaks to protect your house from cold winter winds.
• Do not block the sun from reaching south-facing windows.
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• Shade south and west windows and walls from the direct summer sun if summer overheating is a problem.
Deciduous plants provide summer shade while still allowing low-angle winter sunlight to warm your home during
the coldest months.
Temperate
• Make the most of the warming effects of winter sunshine.
• Make the most of cooling shade in summer.
• Deflect winter winds away from the house.
• Funnel summer breezes toward your home.
Hot and arid
• Provide shade to cool roofs, walls, and windows.
• Landscape around your home so that it is cooled by evapotranspiration, the release of water vapor from the soil
and plant surfaces into the atmosphere.
• Funnel summer breezes toward your home if it is cooled naturally.
• Deflect them away from your home if it is air-conditioned.
Hot and humid
• Direct summer breezes toward your home.
• Make the most of summer shade with trees that still allow low-angle winter sunlight to warm your home.
• Avoid locating planting beds close to your house if they require frequent watering.
How To Plan An Energy-Conserving Landscape
To create the most energy-efficient landscape possible, start by drawing a simple plan. The more you familiarize
yourself with your property’s existing features, whether windows or pavement to be shaded or winds to be deflected,
the better you’ll be able to identify the most effective strategies.
Using paper and different-colored pencils, draw your house and property to scale, allowing ¼ inch for each foot.
Consulting a plat map or site survey can be helpful. Locate walks, driveways, and other paved surfaces, as well as the
garage and/or other outbuildings. Mark all glassed areas, such as windows and doors—sunlight streaming through
east- and west-facing windows can overheat a house in summer, while south-facing glass can help keep it warm in
winter. Also note the presence of any solar collectors or photovoltaic arrays, which should never be shaded. Measure
the height of your house, a crucial consideration both for blocking winds and shading walls and the roof.
Identify north, south, east, and west. Draw arrows to show the angle of the sun in both winter and summer in your
area. Note, for example, how the sun strikes your house between 9 a.m. and 3 p.m. in winter since a south-facing
window or collector receives most solar energy between these hours. Staff at your local library can help you determine
solar angles, and there are also solar position calculators online. To plan for appropriate shade, determine how the
sun strikes the house in summer. Don’t forget the late afternoon when the sun is lower in the sky and shines directly
through windows at a time when the house has already become hot over the course of the day.
Also note the direction of prevailing winds. In the East, the coldest winds generally come from the north and west,
while in the West they come from the north and east, but check online or with the staff at your local library if you’re
not sure. If a windbreak is an appropriate solution, it will need to block the path of these prevailing winter winds.
Next, circle the areas of your home that require shade or can benefit from breezes, and those that need protection
from the wind.
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LANDSCAPE PLAN FOR HOME ENERGY EFFICIENCY
Summer
Sun
Winter
Winds
Winter
Sun
Windbreak
Summer
Breezes
House
Trees
North
East
West
South
Trees
A simple landscape plan will help you devise the most effective strategies for an energy-conserving landscape.
Note which areas of your home are affected by the sun and wind (upper left) to determine the best placement
of plantings (lower right). The plan above is for a home in the eastern states, where cold winter winds generally
come from the north and west.
For More Information
Many states offer online information on landscaping strategies that save energy and money. Often this information
is available through the state Cooperative Extension service. To find your nearest Cooperative Extension office, look
here. (www.csrees.usda.gov/Extension/)
Following are a few good examples of the information that is available:
“Landscaping for Energy Conservation”
(http://aggie-horticulture.tamu.edu/extension/homelandscape/energy/energy.html)
AgriLife Extension, Texas A&M System
“Planting to Conserve Energy”
(www.colostate.edu/Depts/CoopExt/4DMG/Trees/conserve.htm)
Colorado State University Cooperative Extension
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“Essential Elements for Windbreak Design”
(http://web.extension.illinois.edu/champaign/homeowners/081208.html)
University of Illinois Extension
Creating Summer Shade
In regions where summer overheating is a problem, the easiest way to reduce home energy consumption is
with plantings that cast cooling shade. A well-planned landscape can reduce an unshaded home’s summer airconditioning costs by 15 to 50 percent.
What To Do
• Shade your air conditioners.
An easy way to get quick results is to shade your air conditioner. According to the Department of Energy, this can
increase the unit’s efficiency by as much as 10 percent. Just be sure that shrubs or vines planted near the compressor
do not obstruct the air flow or impede access for repairs. See below for ideas on what to plant.
• Shade your walls, windows, and roof.
Solar heat passing through windows and absorbed through the roof is the major reason for air-conditioner use.
Shading can reduce this solar heat gain and cut air-conditioning costs. If you live in a cool region, remember that
your home may never overheat and may not require shading.
• Following are some plants to consider.
A variety of beautiful vines, shrubs, and trees with appropriate sizes, densities, and shapes are available for almost
any shading application. To block solar heat in the summer but let much of it in during the winter, use deciduous
trees. To provide year-round shade in hot climates, use evergreen trees, shrubs, and vines.
Vines
Trees take a while to grow, but you can moderate hot sunshine quickly using vines that clamber up strategically
placed trellises. A wooden lattice put up to support the vines will itself lend a measure of shade from the start.
Permanent structures such as trellises are most appropriate in hot climates where blocking solar heat gain in winter
is not counterproductive. Where wetness and humidity are a problem, keep the trellis at least a foot away from the
house to allow for air circulation; in these areas air should be allowed to flow around the home, keeping the structure
and surrounding soil dry to prevent mildew and rot. Be sure the trellis isn’t under your eaves since hot air that builds
up between the trellis and the siding should be able to vent out. Arbors or pergolas can help shade windows, too, and
are a better choice in temperate regions if the lower winter sun can still penetrate the windows to warm your house.
Annual vines grow quickly and can cover a large area by mid- to late summer. You can make your shading device
twice as functional by growing vines that not only provide shade, but also fruits or vegetables. Edible vines such as
scarlet runner beans, winter squashes, and luffa squashes are both vigorous and fast growing. Ornamental vines are
also good candidates, especially if they offer food and shelter for wildlife. Cypress vine and scarlet creeper provide
nectar for hummingbirds, for example, while moonflower attracts moths.
At the same time, you can plant perennial vines, which may take two or more years to cover an arbor or trellis as
tall as your home’s walls. But unless they don’t block the sun in winter or can be cut back drastically at the end of
the season, avoid planting these in cooler climates where solar heat gain is desirable during the cold months. Edible
perennial vines for warm-winter areas include chayote, kiwi, and passion fruit. Native perennial vines with wildlife
appeal include coral honeysuckle, trumpet creeper, California honeysuckle, and orange honeysuckle, which are all
beloved by hummingbirds, wild grapes, which are eaten by many birds, and pipevines, which have interesting pipe-
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shaped flowers. Species such as Dutchman’s pipe and
California pipevine are host plants for the caterpillars
of pipevine swallowtail butterflies. Be sure to select
non-invasive species that are appropriate for your
region.
Trees and Shrubs
Large trees and shrubs take longer to fill in but
provide the best cooling shade. The air temperature
can be as much as 25 degrees Fahrenheit (F) cooler
under trees than around nearby blacktop. As is true
for vines, in cool and temperate climates placing
trees for summer shade and winter sunshine is more
complicated than it would first appear. What you want
is a cooling device for summer that won’t block out
warming winter sunlight.
Trees can reduce summer temperatures significantly,
especially when they’re located on the south and
west sides of the house. Large specimens that shade
the roof from the afternoon sun can reduce indoor
temperatures by as much as 8 to 10 degrees F. Make
sure you choose trees tall enough when mature to
shade your roof; if they don’t overhang the roof they
won’t cast much shade at midday when the sun is
high in the sky. Set the trees close enough to the
house to cast shade but far enough away, about 15
feet, that their roots won’t damage your foundation.
Also consider how wide the trees will become when
mature, and space them accordingly.
One way to create shade is to grow a vine growing up a
trellis. The vine will do double duty if you grow an edible
variety or a species that provides food for wildlife, like the
native coral honeysuckle above, a hummingbird magnet.
On small city or suburban lots, the optimum location
for a shade tree may be in your neighbor’s yard. Work
with your neighbors to plan and plant an energy-conserving neighborhood landscape that improves conditions and
lowers costs for everyone. If that’s not possible, use shrubs and vines to shade your walls, windows, and air conditioner.
Deciduous trees provide shade in summer, then drop their leaves in autumn, allowing the warmth of the sun to filter
through their bare branches and help heat the home when the weather is cold. Maples and other tall species with
broad leaves and a high, spreading crown are ideal for this purpose. As few as two or three properly spaced trees
with wide crowns may suffice, depending on the size of your house. Prune lower branches for maximum heating of
your walls and roof by the low winter sun.
A 6- to 8-foot deciduous tree planted near your home will begin shading windows the first year. Depending on the
species and the height of your home, it will shade the roof in five to ten years.
Smaller trees and shrubs can play a role in an energy-conserving landscape as well. Species with branches lower to
the ground can be planted closer to the house than tall shade trees and used for shading east- and west-facing walls
and windows from the lower morning and afternoon sun. For the greatest ecological benefit, select species native
to your region to offer food and shelter for pollinators and other wildlife. Shrubs planted close to the house will fill in
rapidly and shade walls and windows relatively quickly. In wet and humid areas, avoid planting them right up against
the house so air can circulate freely.
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Blocking winter Winds
Winds make winter cold significantly worse. Although it’s more difficult to use plantings to reduce the brunt of the
wind than to shade the sunlight, it is possible to keep a house warmer in winter by blocking the chilling effects of the
wind. The most effective way is to plant a windbreak, a band of evergreen trees and shrubs located perpendicular to
the prevailing winds. If your property is small, you can use evergreen shrubs to create a dead air space that can help
insulate your home (see below).
The most effective way to protect a home from winter cold is to plant a windbreak perpendicular to the
prevailing winds (top). Two or three rows of evergreens are ideal. Some air will be able to pass through the
windbreak, but most will be lofted up and over the house. On small properties, a dense evergreen hedge
planted perpendicular to the wind several feet from the house creates a dead air space that can help reduce
the chilling power of the wind (bottom).
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According to the U.S. Department of Energy, if you live in a windy area, strategically placed trees and shrubs can
slash your winter heating bills by a third. Windbreaks have other benefits as well. They can help block undesirable
views and provide a living screen for privacy. Well-designed windbreaks are also aesthetically pleasing in themselves,
and they’re great wildlife habitat. In fact, studies have demonstrated that the windbreaks in the Plains states, which
were promoted in the mid-1930s to reduce soil erosion, are important stopover habitats for migrating birds.
How To Create An Effective Windbreak
To be most effective, a windbreak must meet certain requirements. The extent of protection is related to a
windbreak’s height and length. A windbreak will reduce wind speed for a distance of as much as 30 times its height.
But for the greatest protection, plant your windbreak at a distance from your house of about two to five times the
height of the trees when they’re mature. That means that if the trees you’re planting will grow to 40 feet tall, you
should plant them at least 80 feet upwind from your house. A good windbreak provides protection in more than one
direction. A study in South Dakota found that windbreaks located to the west, north, and east of homes cut their fuel
consumption by an average of 40 percent. Houses with windbreaks planted only on the windward side, the side of
the prevailing winds, averaged 25 percent less fuel consumption than similar but unprotected homes.
The best windbreaks block the wind close to the ground as well as up high, so be sure to include species that have
low crowns, such as spruces and firs. Evergreens can also be combined with a wall, fence, or earth berm to lift the
winds up and over your house.
Some air should be able to pass through the windbreak. Impenetrable barriers create a strong vacuum on the
protected or leeward side, causing some of the wind to whip up over the top and down, slamming into your house
instead of lofting over it. Windbreaks composed of living plants naturally allow some of the wind to penetrate, which
makes them more effective. If you’re using a fence, use an open-weave pattern or remove every other slat.
A newly planted windbreak in Iowa includes two rows of evergreens with branches low to the ground and a row of multistemmed shrubs on the windward side to prevent snow from drifting near the house.
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The depth of the windbreak, not just its height and length, is important. Three rows are ideal, but a two-row
windbreak is still effective, and one row of evergreens is better than nothing if space is limited. How far apart the
trees and shrubs should be planted depends upon the size and shape of the species when they reach maturity, but
there should be no gaps between the plants when they are fully grown. If your budget allows, for quick cover you can
plant them at half the optimum spacing and remove every other one as they fill in. You can use them as Christmas
trees, then for mulch when the holidays are over. If snow tends to drift in your area, plant low, multi-stemmed shrubs
such as red-twig dogwoods on the windward side (outside) of your windbreak. Called a “snowtripper,” this row of
shrubs will reduce the amount of snow deposited near your house.
As with any type of landscaping, select a diversity of plants for your windbreak. Plant at least two to three different
species and preferably more. That way, if a pest or disease attacks, at least some of the trees will survive. One of
the rows should include a dense evergreen species such as spruce. Pines can be included in multi-row windbreaks,
but they’re not as dense as spruces and tend to thin out even more as they mature. On small properties, evergreen
shrubs such as red cedar, arborvitae, or other species appropriate for your region are good choices. The leeward
or inside rows can include smaller shrubs and flowering trees to add interest and increase the planting’s value for
wildlife. Native hollies, dogwoods, elderberries, witchhazels, and viburnums are all useful for this purpose.
How To Create A Dead Air Space On A Small Property
Not every property is big enough to accommodate a full-size windbreak. If you live on a small city or suburban lot,
you can use less substantial evergreen plantings closer to your house to help provide insulation. On large properties
these can be used with windbreaks for additional protection. Dense evergreens that will grow into a thick hedge are
most appropriate. Plant them close enough together to form a solid living wall and several feet away from your house
to create a dead air space, which has much less cooling power than blustery wind. An evergreen planting can also
help shelter a front or back door exposed to the wind.
The Best Evergreens For Windbreaks
Be certain to choose species that are suitable for your region and the specific conditions on your property. A couple
of good candidates for the mid–Atlantic, for example, are American holly and eastern red cedar.
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R e d uc e T h e U r b a n He at Isla nd Effe ct
If you watch local weather reports, you’ve probably noticed that temperatures are often higher in cities than nearby
rural areas. The difference in temperatures is due to a phenomenon known as the urban heat island effect. The
annual mean temperature of a city with one million people or more can be 1.8 to 5.4 degrees Fahrenheit (F) higher
than its surroundings, according to the U.S. Environmental Protection Agency. In the evening, the difference can be
as high as 22 degrees F.
These higher temperatures have a number of effects,
mostly negative, on a community’s environment and
quality of life. They significantly increase the demand
for electricity for air conditioning in summer. The
resulting upsurge in energy consumption at power
plants in turn leads to increases in air pollution,
including greenhouse gases. Elevated temperatures
directly increase the formation of ground-level ozone
in cities. Breathing ozone can trigger a variety of
health problems, from throat irritation and lung
inflammation to asthma attacks. The heat island
effect can exacerbate heat waves, with serious
potential health risks—Centers for Disease Control
figures show that from 1979 to 2003 excessive heat
caused more deaths than hurricanes, lightning,
tornadoes, floods, and earthquakes combined. And
higher temperatures lead to warmer stormwater
runoff, which can harm aquatic life.
What Causes The Urban Heat
Island Effect
When cities are built, vegetation is removed and
typically replaced by buildings with dark roofs and
blacktopped streets. The buildings and pavement
absorb a significant amount of solar radiation and
emit it as heat. Because more than half of the
surfaces in cities are man-made, they heat up more
than less developed rural areas. These surfaces also
hold on to heat and emit it over a period of hours,
which is why the temperature difference between
cities and rural areas is highest in the evening.
Vegetation loss helps drive the urban heat island
effect in another way as well. Vegetation keeps areas
The maps of New York City at right illustrate graphically
how areas with the least vegetation (bottom) are also the
hottest (top).
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cool through the process called evapotranspiration or evaporative cooling. As part of their normal functioning, plants
release water vapor. When the surrounding air absorbs the water, it loses heat and becomes cooler. Because there
are fewer plants in cities, there is less evaporative cooling than in rural areas.
What You Can Do
• Probably the most cost-effective thing you can do to reduce the urban heat island effect in your community is to
plant trees and shrubs to shade your roof, patio, driveway, and walkways. Planting street trees will also provide
much-needed shade. Through evaporative cooling, the plants reduce peak summer temperatures even more.
• When pavement is necessary, light-colored reflective surfaces are better than blacktop or asphalt.
• Green roofs provide shade and remove heat from the air through evapotranspiration, reducing temperatures of the
roof surface and the surrounding air. On hot summer days, the surface temperature of a living roof can be cooler
than the air temperature, while the surface of a conventional rooftop can be up to 90 degrees F hotter. Green
roofs are substantial investments, but are worth considering if you are looking for a new roofing system. Find out
more about them on page 47.
For More Information
An entire section of the U.S. Environmental Protection Agency website (www.epa.gov/heatislands/index.htm) is
devoted to the heat island effect, its causes and impacts, and ways to reduce it.
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M at erials
Landscape materials can cause environmental damage well
before they are installed in a garden. Harvesting and transport
consume energy and generate pollution And the problems
continue even when the materials are dismantled if they are
discarded in a landfill instead of reused or recycled.
Even a seemingly benign material like wood raises questions:
Does it come from a species threatened by the timber trade?
Where was it harvested, and how much energy was required to
transport it to your area?
A sustainable gardener strives to be “zero-waste” by reducing,
reusing, and recycling as much material as possible—including
landscape trimmings and food scraps (see pages 21-26).
The best course of action is to reduce the amount of material
required by downsizing a landscape project if possible. Reusing
material already on your property or salvaged from a nearby
site is another good choice. If you are buying new materials,
opt for natural, untreated, least toxic, and recyclable products
made locally. In addition, to promote recycling you should look
for products with recycled content—the higher the percentage,
the better. Fortunately, a growing number of “certified green”
products are becoming available, simplifying things for
consumers.
Cement production creates
emissions of carbon dioxide, the
major greenhouse gas, equal
to those from 20 million cars,
according to the U.S. EPA.
Conventional And Sustainable Landscapes: How They Compare
Conventional Landscape
Sustainable Landscape
• Often contains materials that pollute air, soil, and
• Made of healthy materials
• Encourages reuse and recycling
• Includes sustainably harvested wood
• Made with local materials, conserving energy
water
• Used materials typically end up at landfills
• Wood choices may imperil tree species
• Made with materials shipped from far away,
and minimizing pollution, including greenhouse
gases
consuming energy and generating pollution
• Supports local businesses and the regional
• Does not support local businesses and the regional
economy
economy
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Re d u c e t h e A m ount of Mater i al
N e ce s s a ry
The first thing to do when selecting landscape products is to examine ways to reduce materials consumption.
We often undertake projects we don’t really need, assume that bigger is always better, and end up eliminating
handsome and functional garden features in our zeal to redo and start over with something new.
To conserve resources—including hard-earned cash—it helps to question these assumptions. In many cases,
intimate can be more pleasant than palatial, and smaller is less expensive and new projects can add to
maintenance.
What To Do
• Start by asking yourself whether a particular garden project you’re contemplating is essential. Do you truly need
a trellis like the one you saw in that home and garden magazine? Is it really necessary to replace your perfectly
functional deck with an elaborate, three-level construction?
• If you decide you do indeed need a new landscape feature, ask yourself if the one you have your heart set
on can be downsized. If you need a patio for socializing or dining alfresco with a small group of friends, for
example, a space big enough for a baronial dining table isn’t necessary. An area 12 feet in diameter can
accommodate a 48-inch round table, which seats six to eight people.
• Consider whether existing structures, retaining walls, paving, furniture, and other landscape amenities can be
incorporated into your design, or moved and enjoyed in another area of your yard.
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Re u s e Ex is t in g and Salvaged
Mat e ri a l s
Reusing materials already on your property, or
those salvaged from a nearby location is more
environmentally friendly than purchasing products
made of virgin resources. It’s usually less expensive,
too. Salvaged materials often have a handsome
aged patina that new products lack. And they can
have a history that adds to their character. Think
about the stories that may be associated with
flagstone salvaged from a local church—how many
times they were trod by brides and grooms, for
example—as opposed to material purchased from a
superstore that typically is not very unique.
What To Do
• Look around your own property and ask your
neighbors for material that can be repurposed. Do
you have a stockpile of pavers behind your garage
that you can use to create a patio or path, for
example? Can wood from your existing deck be
incorporated in a new design?
• Check the growing number of stores and websites
that offer less expensive—or free—used and
salvaged materials and garden amenities.
Following, in alphabetical order, are a few of the
possibilities:
Craigslist (www.craigslist.org/about/sites)
Freecycle (www.freecycle.org)
Habitat for Humanity’s Restore (www.habitat.org/
env/restores.aspx)
It’s a good idea to look around your property for material that
can be repurposed. There may be a stockpile of pavers in or
behind the garage, often with an aged patina and a story,
that can be used to create a patio or path.
The Recyclers Exchange (www.recycle.net/exchange)
The Reuse Development Organization (www.redo.org)
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Av oi d W o o d f r om Threatened
T r e e S p ec i es
Wood would seem to be the perfect material for a sustainable landscape. It’s handsome. It’s constantly renewed
by nature. It links a home with the surrounding landscape, especially in forested areas, enhancing the occupants’
connection to the natural world. If responsible forestry practices have been employed in producing the timber and
the particular tree species used are in plentiful supply, wood is environmentally preferable to many other materials.
But sometimes it is not.
A number of tree species are threatened with extinction due to over-harvesting by the timber industry. Most of
these are tropical hardwoods prized for their coloring and beautiful grain or rot resistance. Globally, there are two
major initiatives that aim to compile a comprehensive worldwide list of imperiled species, control international
trade in endangered species, and promote the sustainable use of timber. You can use these as a resource to make
sure the wood you are considering for purchase does not come from an imperiled species.
What To Do
• The Red List produced by the IUCN, The World Conservation Union, is the most comprehensive global inventory
of the conservation status of plants and animals. It assigns each species a threat category, including CR
(Critically Endangered), EN (Endangered), VU (Vulnerable), and NT (Near Threatened). For example, white
lauan, also known as white seraya, one of the most important commercial timber trees of northern Borneo, is
listed as Critically Endangered.
Some tree species, many of them tropical hardwoods, are threatened with extinction due to overharvesting by the timber
trade. Before purchasing wood for a deck or other project, make sure it does not come from an imperiled species.
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Type in the common or botanical name of a tree in the search box on the Red List home page (www.iucnredlist.
org) to see if it is a species of concern.
• The Convention on International Trade in Endangered Species of Wild Fauna and Flora, better known as CITES,
is an agreement between 175 countries that came into effect in 1975. Its goal is to ensure that global trade in
wild plants and animals does not threaten their survival. CITES allows trade in species that can withstand current
rates of exploitation but restricts trade in those threatened with extinction.
More than 28,000 trees and other plant species are listed by CITES in one of three Appendices, according to
the degree of protection they need. Species in Appendix I, including Brazilian rosewood, are threatened with
extinction, and CITES prohibits international trade of these species except when the purpose is not commercial.
Appendix II lists species that are not necessarily threatened with extinction right now but may become so unless
trade is closely controlled. These include West Indian mahogany, Honduras mahogany, and big-leaf mahogany.
Appendix III is a list of species included at the request of a Party that already regulates trade in the species
and that needs the cooperation of other countries to prevent unsustainable or illegal exploitation. Guatemalan
populations of cocobolo, also known as Nicaraguan rosewood, are among the trees listed in Appendix III.
Use the database of species listed by CITES (www.cites.org/eng/resources/species.html) to check for trees
threatened by international trade. The database can be searched by common name.
• The Global Trees Campaign (www.globaltrees.org/index.htm), a partnership between Fauna & Flora
International and Botanic Gardens Conservation International, is another good source of information on
threatened trees and includes profiles of a number of species threatened by commercial logging.
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C h o o s e C erti f i e d Wo o d
While consumers clamor for lists of wood species to choose and endangered wood species to avoid, many experts are
hesitant to compile or recommend them. Trees become threatened when they are not being harvested sustainably.
Within the same country, a tree species may be endangered in one area and responsibly harvested in another. In
the case of domestic trees like Douglas fir, it is not the species itself but rather the old-growth forests from which
specimens can be cut that are becoming rare.
Traditionally, forests both here and abroad have been managed for maximum timber yield and profit. In order to
be truly a renewable resource, wood must be managed on a sustainable yield basis—that is, it should not be cut
down faster than it can be regrown or replaced by nature in the wild. The term “sustainable yield” has entered
the lexicon of forestry schools only in the past few decades, and it’s just beginning to filter down into the ranks
of foresters in the field. Most forest lands are still managed primarily for just one species and one size of tree in
what are called even-age stands, drastically limiting the diversity of wild plants and animals that can live there.
Ecologically managed forests include a number of environmental protections, such as making riparian zones off
limits to logging to prevent erosion and damage to salmon and trout habitats, and zones of critical habitat for rare
and endangered species. Wood plantations are managed so they reduce pressures on and promote the restoration
and conservation of natural forests.
The best way to guarantee that the lumber and other wood products you purchase have been harvested sustainably
is to choose products certified by the Forest Stewardship Council (FSC) (www.fsc.org) or other independent
nonprofit organizations which have determined that the materials meet a set of rigorous standards. Information on
the FSC standards, the certification process, and how to find suppliers is available on the website of the U.S. chapter
of the FSC (www.fscus.org).
What To Do
• Look for products bearing the FSC logo, which are available from a variety of
mills, manufacturers, and distributors.
• To support the regional economy and conserve energy, purchase products that
have been harvested and manufactured locally rather than shipped across the
country or from the tropics.
More Wood Tips
To maximize the benefits to the environment as well as the local economy, here are some other
tips to keep in mind when shopping for wood:
•R
eusing materials already on your property or those salvaged from a nearby location is more
environmentally friendly than purchasing products made of virgin resources. It is usually less
expensive, too.
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•T
o eliminate offgassing or leaching of toxins into the air, soil, and water, do not purchase
wood that has been treated with chemicals. Instead, choose a naturally rot-resistant species
grown in your area.
• S ometimes wood from regionally invasive tree species is available. By buying it you help solve
two problems at once—you use a local material and also promote the removal of trees that
threaten natural areas.
•K
eep in mind that wood may require maintenance over its lifetime. When paints or other
finishes are necessary, choose the least toxic products available.
Many forests, like this one in Oregon, are still clearcut, causing substantial ecological damage. Choosing certified wood
ensures that it has been harvested sustainably.
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P ur ch a s e o th er Ce rt ifie d Pro du c t s
With almost every company rushing to polish its environmental credentials these days, it’s becoming difficult to
distinguish the truly green from the “greenwashed.” For this reason, it makes sense to look for products and services
that have been certified by an independent organization that has determined they meet a set of environmentally
rigorous standards.
The group behind an eco-label should make information on its organizational leadership and funding, as well as the
standards it uses to certify products, available to the public. Below are some of the most respected green product
certifiers. Several provide so-called single-attribute certifications, which address a specific environmental issue—
sustainable forestry or indoor air quality, for example. Others are multiple-attribute eco-labels that consider a number
of factors.
What To Do
Following, in alphabetical order, are some independent certifiers that are particularly useful for homeowners and
gardeners. When you are searching for a landscape material or
product, check on their websites for certified brands.
coLogo
•E
Launched by the Canadian government in 1988, EcoLogo (www.
ecologo.org/en/greenproducts/consumers/) has grown to certify
thousands of products for buyers throughout the U.S. and Canada
and around the world. Search the the EcoLogo products and
services directory for consumers, which includes everything from
paints, sealers, caulks, and other building products to garbage
bags.
nergyStar
•E
EnergyStar (www.energystar.gov) is a national certification
system developed by the U.S. Environmental Protection Agency
and Department of Energy to promote energy-efficient products
and homes. Among the products that have attained EnergyStar
certification are LED lights for outdoors.
orest Stewardship Council
•F
The Forest Stewardship Council (FSC) (www.fscus.org) is a
nonprofit organization that has developed an international standard
for responsibly managed forests and certifies the wood and paper
products derived from them. Products and rankings can be found
on the FSC website. You can find more information on the FSC
here.
reenguard
•G
Greenguard (www.greenguard.org/) certifies that products meet
low emission standards for a number of indoor air pollutants,
including formaldehyde and other volatile organic compounds
(VOCs). Some of these products, such as paints, adhesives, and
sealants, can also be used outdoors.
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reen Seal
•G
Green Seal (www.greenseal.org) began certifying products in 1992. Since that time, Green Seal has put its
imprimatur on a wide range of products, including paints and other types of finishes.
• I nternational Dark-Sky Association
Formed in 1988, the International Dark-Sky Association (www.nextrionet.com/mc/page.
do?sitePageId=56421&orgId=idsa) is the authoritative voice on light pollution. The IDA Fixture Seal of Approval
certifies outdoor lighting systems that minimize harm to human health and nocturnal wildlife. Scores of products
have been certified so far.
rganic Materials Review Institute
•O
The Organic Materials Review Institute (www.omri.org), or OMRI, is an independent reviewer of products used
by certified organic growers and suppliers. The OMRI Products List, a directory of all products the organization has
determined are allowed for use in organic production, includes everything from earthworm castings to composts
and mulches. Available on the OMRI website, the easy-to-use database can be searched by product (compost
tea, say, or potting media), category (such as soil amendments), or manufacturer. Contact information for each
manufacturer is provided, making it relatively easy to track down a particular product.
ustainable Choice
•S
Launched by Scientific Certification Systems, which has been providing auditing, testing, and certification
services since 1984, Sustainable Choice (www.scscertified.com/products/) includes both environmental and
social standards. You can search their online green products database for a variety of products, such as paints,
adhesives, sealants, and recycled rock mixtures.
aterSense
•W
Sponsored by the Environmental Protection Agency, WaterSense (www.epa.gov/watersense) seeks to do for
plumbing fixtures and irrigation services what the EnergyStar label has done for electronic appliances. A variety of
water-conserving irrigation technologies and services that have been awarded the WaterSense label are listed on
the program’s website.
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S e l e c t L o c a l M at e ria ls and Pro du cts
Using materials produced in your region has multiple advantages. It reduces the fossil fuels required for shipping
and associated pollutants, including greenhouse gas emissions. It supports local businesses and feeds money into
the regional economy. And one of the beauties of landscaping with local materials is that they seem to belong and
enhance your region’s unique sense of place. What could be more emblematic of the desert Southwest, for example,
than adobe walls made with local soils?
What constitutes “local” varies to some extent, depending on the type of material. The heavier the material, the more
energy it consumes and the more pollutants emitted during transport, and therefore the closer the source should be.
For example, to qualify as local under the Sustainable Sites Initiative, on which Landscape For Life is based, crushed
concrete and other aggregates used as a foundation for paths and driveways must be extracted, recovered, or
manufactured within 50 miles of the site. Compost and other soil amendments must also come from within 50 miles.
Plants, which are relatively light, must be grown at a facility within 250 miles. Other materials must be extracted,
harvested, recovered, and manufactured within 500 miles.
What To Do
• Identify local sources for wood, plants, and other landscape materials, including those that are reused, salvaged,
or contain recycled content—preferably in the planning stage of your project, since the availability of materials may
influence design choices.
To reduce the amount of energy required for shipping and the associated pollutants, including greenhouse gases, purchase
wood and other products that have been produced locally.
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U se C o n c r ete A lt e r nat ive s
The use of concrete in home construction dates back at least 2,000 years to ancient Rome. The ruins of Emperor
Hadrian’s villa near Rome reveal that some walls and domes were constructed with a mixture of volcanic tuff and
sand very much like modern concrete. The development of portland cement in 1824 by an English inventor led to
the first major improvement in concrete technology, and today concrete is one of the most commonly used materials
in residential and other construction—with a variety of landscape uses, from paths and patios to driveways, planters,
and mortar.
Although the words concrete and cement are often used interchangeably, there is technically a difference. Concrete
is comprised of three major components: aggregates, usually a mixture of coarse and fine materials such as gravel,
crushed stone, and sand; Portland cement, which binds it all together; water; and various chemicals. Portland
cement is made from lime, silica, iron, and alumina. Mortar, which is used to hold brick or stone together, is
composed of cement and sand.
Cement, the most important component of concrete, requires a staggering amount of energy to manufacture and
results in considerable carbon dioxide emissions. After they are mixed together, the lime, silica, iron, and alumina are
heated to about 2,700 degrees Fahrenheit in a kiln, usually fired by fossil fuels, to make a pellet-like material called
clinker. After cooling, the clinker is ground into a powder and mixed with gypsum.
This handsome patio was made from existing concrete that was broken up into flagstone-size pieces. Recycling the
concrete conserved energy, minimized the pollution associated with cement manufacture, and kept the material out of a
landfill.
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What To Do
• If you’re paving a driveway, pathway, or patio, using recycled concrete is a good option. Existing concrete is
broken, crushed, or screened. It can then be used as flagstone-size pieces for patios and pathways, as crushed
gravel, or as an aggregate base for crushed stone or other paving material. It can also be reprocessed as poured
concrete for a path, patio or other hardscape feature, or made into concrete pavers. Making use of existing
material minimizes the energy required for manufacturing and eliminates the need for disposal.
• Crushed limestone, crushed granite, or, even better, crushed recycled materials such as clamshells are other
alternatives to conventional concrete. Crushing materials uses much less energy than manufacturing cement.
• If your landscape project requires concrete, look for a product that contains a cement substitute such as
recycled fly ash, a by-product of coal-fired electric generating plants, or slag, a waste product of the smelting
and refining of metals.
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S e l e c t M ater i a ls That Do No t
P o l l u te S to r m wat e r
When rain or snowmelt flows off your roof onto impervious surfaces like driveways and sidewalks, it can pick up
chemicals, nutrients from excess fertilizer, heavy metals, and other pollutants and carry them into streams, rivers,
lakes, wetlands, and coastal waters. This polluted stormwater runoff can have a variety of harmful effects on plants,
fish, animals, and people. By carefully choosing materials for your landscape, you can help keep pollutants out of
stormwater runoff.
Some materials can leach heavy metals such as copper and zinc. These include galvanized corrugated steel used
for roofing and other products; zinc roofing, cladding, shingles, and down-pipes; and copper flashing, gutters,
vents, and decorative landscape elements. Heavy metals can be toxic to fish and other aquatic life. They can also
bioaccumulate in aquatic species, such as mussels, and in turn throughout the food chain, to humans. Heavy metals
accumulate in the human body and over time can reach levels that are toxic and cause serious health problems.
From the 1940s until 2003, chromated copper arsenate (CCA) was commonly used to pressure treat wood for rot
resistance. Since 2003, no wood treater or manufacturer may use CCA to treat wood for decking, playsets, and other
residential uses. (It’s still used for marine pilings and utility poles.) There are several arsenic-free treatments on the
market, including borates, but these options are not risk free and should not be used outdoors where they will come
into contact with water.
What To Do
• If you are in the market for a new roofing system, consider alternatives to galvanized, copper, and zinc products
such as wood shingles, slate, and baked enamel painted metal products, or a green roof.
• Use sustainably harvested rot-resistant woods native to your area as an alterative to treated wood for fence posts,
raised beds, and other landscape applications.
• Coal tar sealants, better known as blacktop, the shiny black material applied to many driveways, are high in
polycyclic aromatic hydrocarbons (PAHs), which contribute to pollution of many of the nation’s urban lakes.
PAHs are toxic to aquatic life and several are suspected carcinogens. Blacktop is also impermeable. Use less toxic
materials such as crushed seashells, which would otherwise be disposed of as a waste, or gravel obtained locally.
• Minimize use of fertilizers and pesticides. Excess nutrients from overuse of fertilizer can cause algae blooms. When
algae die, they sink to the bottom and decompose in a process that removes oxygen from the water. Fish and
other aquatic organisms can’t exist in water with low dissolved oxygen levels. Insecticides and herbicides present in
stormwater can poison aquatic life. Land animals and people can become sick from eating contaminated fish and
shellfish or drinking pesticide-contaminated water.
• Use alternatives to rock salt for deicing. Rock salt can leach into the soil, changing its chemical composition, and
flow into local waterways where it can poison fish and aquatic organisms. It can also harm sensitive plants. Salt is
highly corrosive to paved surfaces, buildings, and metal (it is really bad for your car). And it hurts your pets’ paws.
Alternatives include materials that increase traction, such as kitty litter and sand. For situations where a product that
actually melts ice is required, look for rock salt substitutes such as those made with beet juice extracts, a byproduct of
beet sugar production that would normally be disposed of as waste. Magnesium chloride, which is safer to use near
plants than rock salt but not as effective in very cold conditions, is another possibility.
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C h o o s e n o - o r Low-VOC Pro du c t s
VOCs, or volatile organic compounds, refer to a large number of mostly petrochemical-derived substances that
readily volatilize, or become a gas, at room temperature. VOCs can be bad for the environment and harmful to
human health. Among the hundreds of VOCs found in consumer products are formaldehyde, benzenes, toluene,
styrene, xylenes, and chlorinated solvents such as trichloroethylene, carbon tetrachloride, and methylene chloride.
Landscape products that contain VOCs include primers, paints, stains, sealers, and other finishes, paint strippers,
adhesives, caulks, and pesticides.
When used outdoors, VOCs contribute to the formation of ground-level ozone, which is the primary component of
smog. They have been linked to a variety of negative health effects including dizziness, irritation of the eyes and
respiratory tract, damage to the nervous system, and cancer.
What To Do
• Purchase low- and no-VOC products. While VOCs were once necessary for good performance in many products,
most companies now produce effective and cost-competitive alternatives. For example, less toxic paints, stains, and
varnishes use water as a carrier instead of petroleum-based solvents to reduce emissions.
Check product labels and literature for information on VOC content. Usually listed in grams per liter, it can
range from 5 to 200. Using a product with the lowest VOC content will yield the lowest overall environmental
and health risk. Paints that meet the Green Seal standard are certified lower than 50 g/l for flat finish or 100 g/l
for non-flat finish.
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H uman He alth
Home landscapes are a place to gather with family and friends,
strenghtening social ties and improving relationships. They are
also a safe place for children to play.
Gardens also offer opportunities for physical exercise, which
can reduce the risk of chronic diseases such as coronary heart
disease, strokes, diabetes, and some cancers. Plants cleanse
the air we breathe, removing pollutants that can trigger asthma
and other illnesses. Growing an edible garden can minimize
exposure to the pesticide residues found on most conventionally
grown crops while providing a steady source of the freshest and
most flavorful produce.
In our often hectic modern world, a home landscape can also
be a quiet refuge. Studies demonstrate that the contact with
nature afforded by gardens can reduce stress and improve
psychological well-being.
In fact, our gardens are where many of us have our only daily
contact with the rest of nature. This connection to the larger
web of life is especially important to the more than 80 percent of
Americans who live in towns and cities.
Studies show that encounters
with everyday nature, like a
stroll through a garden, restore
concentration, calm anxiety, and
reduce aggression in adults and
children.
Conventional And Sustainable Landscapes: How They Compare
Conventional Landscape
Sustainable Landscape
• Is often treated with synthetic pesticides
• Vegetable garden is typically irrigated with drinking
• Beneficial insects and other natural processes help
manage pests
• Vegetable garden is irrigated with alternatives to
water
potable water
• Outdoor fixtures waste energy and create
• Outdoor fixtures result in a minimum of light
unhealthy light pollution
pollution
• Is frequently constructed with polluting materials
• Is constructed with healthy, local materials
such as treated wood
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G r o w A F o o d G a r de n
A vegetable garden can be a perfect blend of beauty and utility, a place that stimulates all the senses, including
taste. Nothing beats the flavor and freshness of homegrown produce. And when you grow your own food
organically, you can be sure you’ve minimized your exposure to pesticide residues, which are found on most
conventionally grown crops.
Backyard food production can also be good for the environment. Much of the recent discussion of the
environmental footprint of food has focused on tallying “food miles,” the distance food travels from field or pasture
to table. And nothing is more local than food grown just steps from your kitchen.
But the number of food miles isn’t the only measure of environmental impact. Often a gardener’s biggest
contribution to greenhouse gas emissions arises from the use of nitrogen fertilizers, says David Wolfe, Professor of
Plant and Soil Ecology at Cornell University. The manufacture of synthetic fertilizer is extremely energy intensive.
Manures and other organic sources are better because the carbon dioxide emissions associated with manufacture
are mostly eliminated. But using either synthetic or organic fertilizers releases nitrous oxide, a greenhouse gas
with 300 times more heat-trapping ability per molecule than carbon dioxide. Excessive use of fertilizer can
pollute stormwater runoff and is associated with a host other problems as well. Chemical pesticides used in some
vegetable gardens are also energy intensive to produce, and they are toxic.
In addition, vegetables and fruits generally require more water than they’re likely to receive as rainfall. Most
homeowners make up the difference by irrigating with municipal drinking water, putting more pressure on often
scarce and expensive potable water supplies.
A community garden like the one above is a good option if you don’t have room at home to grow edible plants.
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Beautiful vegetable varieties such as Swiss chard, above, can be tucked into flowerbeds.
Tips For A Sustainable Vegetable Garden
Following are some ways you can maximize the beauty and productivity of a kitchen garden while minimizing its
environmental impact.
• If you’re new to vegetable gardening, start by incorporating some edible plants in appropriate spots throughout
your landscape.
An edible garden doesn’t have to be a separate area of your property. Tuck some favorite herbs and beautiful
vegetable varieties like ‘Ruby’ or ‘Rainbow’ chard into your flowerbeds. Instead of planting junipers, liriope, or
cotoneaster, try strawberries as a groundcover. Blueberry bushes are a good substitute for a privet hedge. And try
planting a fruit tree or two. Even if your yard is small, there’s likely to be a suitable variety of apple, pear, cherry,
peach, plum or other fruit. Dwarf varieties generally reach a height of 6 to 10 feet and should bear fruit in three to
four years. Semi-dwarf varieties grow 15 to 20 feet tall.
• Garden organically.
Take advantage of natural biological processes to increase soil fertility and manage pests, instead of resorting
to synthetic fertilizers and pesticides. Amending your soil with compost improves soil structure and the growing
environment for your plants and provides them with essential nutrients. Mulching the garden helps conserve
moisture and keep down weeds. And growing organically means there will be no synthetic pesticide residues on
your food. Find out more about limiting your exposure to pesticides on page 100.
• Use alternatives to potable water for irrigation.
With a little ingenuity, you can put captured rainwater, air conditioning condensate, or other alternatives to
potable water found in and around the typical home to work in the garden instead of literally throwing it down
the drain. Be sure that you do not use graywater from sinks, showers, and other sources, on food plants, however,
because it can be contaminated with soaps and pathogens. A guide to water-thrifty irrigation practices that can
help you make the most of these alternative water sources is on page 39.
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• Avoid over-cultivating your soil.
A number of recent books have helped popularize the practice of gardening without rototilling or even digging.
Specific no-till practices can vary among authors and practitioners, but the fundamental principle is the same—
dispensing with cultivation as much as possible because it disturbs the soil, encourages weed growth, and
generates greenhouse gases. Instead, compost and organic mulches are used to prepare planting beds, feed
the soil organisms that promote soil fertility, and keep down weeds.
• Grow your plants from seed.
Consider all the resources necessary and pollution that results from buying plants in plastic pots, even seedlings
in cell packs. Growing plants from seed significantly reduces the environmental impacts of transport and
packaging. Growing plants from seed you collect yourself from your own garden eliminates transport and
packaging entirely. Growing from seed enables you to grow disappearing local heirloom varieties (see below),
which often are not available for purchase as plants at the local nursery. Seed is also less expensive than plants.
And most people find it personally rewarding to experience the growth of plants from start to finish.
• Grow heirloom fruits and vegetables.
For centuries, humans played a major role in diversifying the gene pools of crop plants. Wherever we went,
we carried the major food species with us, and wherever we took them, they were modified by the new
environment. In this way, hundreds of locally adapted varieties of the same crop evolved.
Modern, mass-produced cultivars of food crops have some desirable characteristics, including resistance to
diseases—verticillium wilt in a tomato, for example. However, as modern agriculture and kitchen gardening have
come to rely on mass-produced seeds, heirloom fruits and vegetables adapted to various regions have become
increasingly rare. The same modern crop-breeding techniques that have led to some important improvements
have also resulted in a high degree of genetic uniformity in the food plants that sustain us.
The genetic vulnerability of modern crop cultivars became a widespread concern in 1970, when an epidemic of
southern corn-leaf blight destroyed about 15 percent of the U.S. corn crop. The epidemic had two primary causes:
The corn crop uniformly lacked the genes that confer resistance to leaf blight, and the same susceptible variety
was used over a vast area. This kind of vulnerability is becoming an issue for many crops as their genetic base
narrows.
Growing heirloom varieties such as ‘Blue Jade’ corn, a beautiful cultivar suitable for boiling, or ‘Strawberry’,
which is great for popping, helps promote the genetic diversity of crops and can also help preserve your region’s
culinary history. Heirloom varieties suited to the precipitation levels in your area will require less irrigation. And by
growing heirlooms selected for their proven disease resistance, you can help reduce your garden’s dependence on
pesticides.
For More Information
Non-profit organizations like the Seed Savers Exchange (www.seedsavers.org) and the Organic Seed Alliance
(www.seedalliance.org) encourage organic practices and support crop diversity by offering membership discounts
on heirloom seeds and organizing community seed swaps.
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Lim i t Y o u r E x p osu r e To Pe st ic ide s
When most people think of pesticide use, they think of agricultural land. But pesticides typically are applied at
much higher rates to residential landscapes than to farms—20 times higher, according to the U.S. Environmental
Protection Agency (EPA).
The enormous quantity of pesticides used in home landscapes raises a number of health and environmental
concerns, starting with the potential for accidental poisonings of humans and pets. The possibility of cancer
or other illnesses as a result of nonaccidental, chronic exposure to yard pesticides is the subject of an ongoing
scientific debate. Children, whose internal organs are still developing, are particularly vulnerable to the health
problems pesticides may pose. Although pesticides and their use are regulated by the EPA, the uncertainty over
the long-term effects of exposure to even low levels led the American Medical Association to recommend that we
limit exposure to these chemicals and use safer alternatives.
Overuse of pesticides is contributing to the chemical load not just in our bodies, but in the environment at large.
It’s estimated that 5 percent or less of the insecticides and herbicides we spray ends up on the target pest. The
rest ends up on plants, in the soil, and in the air—and via drift, it can also land on any nearby people or pets.
Pesticides in runoff find their way into drinking water supplies and local waterways; pesticide pollution was found
in every stream and over 90 percent of the wells sampled in a study by the U.S. Geological Survey. In waterways,
pesticides can kill fish and other aquatic life. It’s believed that pesticides kill millions of birds each year, and
can impair the ability of others to reproduce. They’ve been linked to the decline of frog populations, as well as
earthworms and other important soil animals. They’ve also led to the loss of pollinators and the beneficial insects
that would otherwise help keep pest populations in our landscapes in check.
One of the best ways to minimize your exposure to the pesticide residues in most conventionally grown crops is to grow
some herbs, vegetables, and fruits at home, avoiding the use of synthetic chemical pesticides.
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What To Do
ne of the best ways to minimize your exposure to pesticide residues in food is to grow some herbs, vegetables,
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and fruits at home, avoiding the use of toxic and persistent synthetic chemical pesticides.
se one of two proven systems, organic gardening or integrated pest management, to eliminate or drastically
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reduce the amount of pesticide you apply throughout your landscape. If you hire a company to care for your
lawn or garden, make sure it is one that employs these least toxic approaches.
Organic Gardening
It’s generally known that organic gardeners refrain from using synthetic fertilizers and pesticides on their plants.
But organic gardening is a lot more than that. It promotes and enhances natural diversity and biological cycles to
make the garden self-sufficient and sustainable, beginning with building and maintaining soil fertility by adding
compost and other organic matter. See the Soils section of the workbook for ideas on how to get started. The
second key to successful organic gardening is choosing plants suited to your climate and the growing conditions
on your property, because these are best able to grow without a lot of added water, fertilizer, and drastic pest
controls.
Organic gardeners employ a variety of other common-sense techniques when necessary to keep their plants
healthy. Most of these involve good growing practices that help prevent pest outbreaks, and outsmarting potential
pests before they overwhelm plants rather than simply blasting them with toxic chemicals. Let’s say you’re in the
vegetable garden and notice that one of your bean plants is
being chewed to bits. What do you do? First, you examine
the plant carefully for signs of the pest. More times than
not, you can solve the pest problem the minute you see
it, by picking it up and crushing it or dropping it into a
container of soapy water. There are many other so-called
physical controls as well, from simple, 3 inch-tall collars
made of cardboard or newspaper placed around plants
to keep out cutworms, to rowcovers, thin and lightweight
fabrics developed in the past few decades that let in rainfall
and plenty of sunlight for growth but are impenetrable even
by tiny insects.
Organic gardeners also make their landscapes havens for
the natural predators of plant pests. Many homeowners
have pest problems at least in part because their yards are
not inviting to so-called beneficial insects, the tigers and
barracudas of the insect world which in natural ecosystems
keep herbivorous insects in check. Although a number
of biological pest controls, the fancy term for beneficial
insects, are sold at local nurseries and by mail-order
suppliers, the most effective way to attract predators to
your yard is to grow asters, coneflowers, and other daisylike
native wildflowers, as well as popular culinary herbs such
as dill and parsley that produce inverted parasol-shaped
inflorescences.
To help keep pest populations in check, grow sunflowers
and coreopsis (above) as well as coneflowers, asters,
and other daisy-like native wildflowers.
Organic gardeners use natural alternatives to synthetic
pesticides, including biological controls such as Bacillus
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thuringiensis (Bt), a bacterium that occurs naturally in soils around the world. Different strains of Bt produce
toxins that affect different insects, including the caterpillars of gypsy moths, hornworms, and cabbage worms
as well as the Colorado potato beetle and other leaf beetles. Insecticidal soaps applied as dilute sprays (1 to 3
percent concentration) are especially effective against small, soft-bodied species such as aphids and spider mites.
Botanical insecticides such as sabadilla and neem, which are derived from plants, are sometimes used as a final
resort. Botanicals can be toxic and must be handled with caution, but most do less ecological damage than
synthetic pesticides because they break down relatively rapidly when exposed to heat, light, or water.
If you’re just starting out as an organic gardener, a basic guide to organic growing techniques is a good
investment. Organicgardening.com (www.organicgardening.com), the website of Organic Gardening magazine,
has a wealth of useful tips. The Organic Materials Review Institute website includes the OMRI Products List (www.
omri.org), a directory of all products the organization has determined are allowed for use by organic growers.
Integrated Pest Management
Integrated pest management, or IPM, is another commonsense approach to pest control that includes many of
the techniques used by organic gardeners but does not rule out the use of synthetic pesticides as a last resort.
Although it was developed initially to help commercial farmers avoid spraying on a regular schedule whether it was
necessary or not, it has been adapted for home gardeners and can be effectively employed with or without the use
of synthetic pesticides.
IPM is a systematic process involving prevention, monitoring, and choosing the least toxic pest control when
action is necessary. One of its fundamental principles is that not all insects and weeds require control. Many are
innocuous, and some are even beneficial. Another is the recognition that when it’s advisable to intervene, the goal
is pest control, not eradication.
Monitoring your plants as often as possible throughout the growing season is the cornerstone of IPM. When you
do encounter a pest problem, you need to learn about the extent of the damage it can cause, and what will
happen to the plant with or without treatment. Seeing a single pest doesn’t mean that action must be taken—you
should continue to keep a watchful eye on your plants, and decide how much damage is acceptable.
As in organic gardening, taking steps to prevent pests from becoming a problem is another basic IPM practice.
This may mean using cultural practices, such as keeping your planting beds clean of any infected plant material,
moving vegetables to different areas of the garden annually to prevent a build-up of pests that live in the soil, or
planting a variety of flowers that provide pollen and nectar for beneficial insects.
If you determine that action against a particular pest is essential, the next step is finding the least toxic yet effective
way to deal with the problem. Physical controls, such as picking the pests off your plants by hand, blasting them
with a strong stream of water to wash off pests like aphids and mites, or protecting them with row covers, are the
first options to consider. Biological controls like Bt can provide control with minimal impact.
If chemical control is the only solution to your pest problem, the goal is to spray with the least toxic and most pestspecific product available before resorting to more toxic and persistent synthetics. These include insecticidal soaps
and Neem-based or other naturally derived pesticides. Unlike products designed to target the pest you’re trying
to control, broad-spectrum pesticides destroy both harmful and beneficial insects. Not surprisingly, the pests reestablish themselves a lot faster than the beneficial species.
For More Information
For more information on the best IPM controls for your area, contact your state or local Cooperative Extension
office (www.csrees.usda.gov/Extension/).
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R e d uc e Li g h t P ollu t ion
It’s an unfortunate fact of modern life that many children and adults have seen a dark sky spangled with stars only
in a planetarium. The night sky in cities and many suburbs is filled not with stars but rather the pervasive orange
haze of artificial light. Scientists are discovering that this light pollution may have serious effects on human health
and can disrupt the normal behavior of wildlife.
Specified periods of light and dark, known as circadian rhythms, are essential for healthy life on earth. Darkness is
as necessary as daylight to our own biological clockwork. Researchers have recently established, for example, that
exposure to artificial light at night reduces the body’s production of melatonin, the hormone that tells our organs
and systems that it is dark. Less melatonin may not seem like a big loss, but studies have consistently proven
that low levels are extremely detrimental, with sweeping health effects across the body. Although the connection
between melatonin and cancer is still unclear, reduced levels have been linked to the growth of breast tumors in
women and may also affect other cancers, including prostate cancer.
The continual state of artificial twilight can have adverse effects on frogs and bats, fireflies and fish, and many
other species. Activity levels often change, for example. Some owls take advantage of the situation and hunt more.
Insects can be fatally drawn to light, often pursued by foraging bats. Some animals are prone to breed more,
others to breed less. Female fireflies produce their trademark flashes to attract males only when there is a certain
level of darkness. Because lighting systems make the night too bright in many areas, they are not attracting males
and are failing to reproduce. The combined effects of light pollution on large numbers of nocturnal species have
the potential to disrupt the functioning of entire ecosystems by disrupting balances in competition and predation.
Light pollution is largely the result of badly designed light fixtures that are unshielded and allow artificial light
to shine outward and upward into the sky, instead of focusing it downward where it is needed. We light our
landscapes at night because we think it makes us safer, but glare from unshielded fixtures can actually make yards
less safe by distracting the eye and casting harsh shadows that can help conceal an intruder. Specially designed
outdoor lighting fixtures that are shielded at the top and sides to reduce light pollution are much more effective at
drawing attention to an unwanted presence, especially when they are triggered by motion sensors. And because
every bit of illumination is directed where it can make a difference, they typically require a lower wattage bulb,
conserving energy and saving money.
What To Do
se outdoor lights at night only when and where they’re needed, and hook them up to motion sensors to
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increase their effectiveness and timers to shut them off when illumination is no longer necessary.
• P urchase exterior lights that have been certified by the International Dark Sky Association (IDA), a nonprofit
educational organization that is the leading authority on the problems of light pollution and commonsense
solutions. Look for the “IDA Approved Dark-Sky Friendly Fixture” label when you shop for outdoor lights.
The IDA website (www.darksky.org/) includes information on approved fixtures, including manufacturers and
distributors. You’ll also find a practical guide for homeowners (http://docs.darksky.org/PG/PG3-residentiallighting.pdf) on effective and efficient outdoor lighting.
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C r e at e G a r den Spac e s Th at Enha nce
H e a lth a nd W el l-Be ing
Having a garden that enhances your health and well-being isn’t just a matter of avoiding exposure to potentially
hazardous pollutants. You can also create special spaces in your landscape that encourage physical fitness, make
interaction with family and friends more enjoyable, and provide havens for quiet relaxation and renewal—unlike
the typical home landscape, which can be a bigger source of stress than of pleasure, with its expanses of lawn that
need to be mowed and overgrown foundation shrubs that cry out for pruning.
What To Do
• Make room for sports and other physical activity.
Lack of physical activity is a recipe for obesity and a host of chronic ailments, from diabetes to heart disease.
According to the Centers for Disease Control (CDC), nearly three-quarters of Americans don’t get the
recommended 30 minutes of physical activity on most days. It’s hardly surprising, then, that more than one-third
of us are obese, and the prevalence of childhood
obesity has tripled in the past 30 years.
Research shows that moderate daily activity decreases
the incidence of chronic diseases. Physical exercise
can also improve mental health by reducing stress and
alleviating depression and anxiety. Since most of us
spend 20, 30, 40, or more hours a week at work or
school, it makes good sense to design home landscapes
that entice us to get moving in our free time.
If you have small children, consider all of the ways to
get them outdoors and engaged in active play—from
sandboxes and seesaws to pogo sticks, playhouses,
and swing sets.
Make sure to create room in your landscape for fun
adult activities, too, whether volleyball, badminton,
bocce, croquet, or a simple game of frisbee. Include
a convenient area for bicycle storage—nothing
makes going out for a ride less likely than having to
move the lawnmower, baby carriages, garbage bins,
or a pile of bricks out of the way first.
Keep in mind that gardening itself is a great form of
exercise. Turning your compost pile works out the
upper body. Raking and mulching trains your upper
arms, shoulders, chest, and back, while squatting
or bending over to pull weeds by hand is good
for your thighs and glutes. And you can get your
heart pumping by taking a turn or two around your
Consider all the landscape features, from children’s gardens
regionally appropriate lawn with a push mower. In fact, to play sets, that will entice youngsters outdoors and engage
them in exercise and active play.
gardening can burn an average of 300 calories per
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hour and is an effective form of resistance training, says the CDC. The agency recommends getting out there three
times a week for 30 minutes to an hour.
• Include space for socializing with family and friends.
There’s a lot of evidence linking social connectedness to health and happiness. The benefits of social ties
range from increased resistance to colds and even dementia to better survival rates for cancer patients. They’re
important not just for individuals but also for the healthy functioning of social groups, including families.
Think about ways you can improve your landscape to make socializing more enjoyable. Can you create or spruce
up a patio or deck for convenient barbecuing, or dining al fresco with the family? Is there a pleasant space in your
garden for sitting and conversing with friends? Can an open area you use for frisbee accommodate larger gatherings
to celebrate birthdays, anniversaries, graduations, and other important milestones?
It helps to sketch out the most desirable places for sitting areas and gathering spaces, as well as the way to get to
them. Convenience and comfort are key considerations: A patio or deck reasonably close to the kitchen, surrounded
by luminous plants, can be a perfect place for evening meals. A breakfast terrace can be located to catch the warm
morning sun. To invite lingering with family and friends, social areas should be out of the sun or wind. You can also
use awnings, vine-covered arbors, or hedges to cast cooling shade or block heavy winds. And make sure there are
enough comfortable places to sit.
Beautiful plantings will enhance any social experience. In outdoor living spaces, flowering trees, shrubs, and
perennials in pleasing arrangements can not only define space, cast shade, and block the wind but also function as
living ornaments. Accessories, from traditional urns and statues to offbeat garden gnomes and gazing balls, give you
an opportunity to express your creativity and can act as conversation pieces.
• Create a quiet garden refuge.
The idea of the garden as a sanctuary is as old as the garden itself. As modern life has become more hectic,
garden havens have become all the more essential. Home landscapes can provide daily opportunities to be
unplugged and unwired, and to seek connections more fundamental than cell phones and texting.
Garden refuges can be as individual as the people who create them, but they do share some common elements.
Many are gardens of the senses, where the sound of grasses rustling in the breeze or the fragrance of a flower can
reduce stress, promote peace of mind, and invite repose. They invite you to linger, and encourage a connection with
the natural world. The most restorative gardens involve you in the drama of nature, whether shifting shadow patterns
cast by trees or shrubs throughout the day or the changing of the seasons—from the unfolding of the first flowers to
the ripening of fruits and the turning of leaves.
A key step in transforming a garden space into a retreat is creating a sense of quiet, enclosure, and privacy. The
trickle of even a small water feature can mask the din of the world outside. The side of your house, stone or adobe
walls, fences, pergolas, hedges, or even strategically placed potted plants can all be used to create a sense of
enclosure. Trees and shrubs can also serve as the “ceiling” and “walls” of a garden sanctuary. Enclosed doesn’t
necessarily mean entirely walled off, however. A quiet garden space that offers views of a distant mountain can be as
effective as a tiny rock garden.
Plants not only help create a sense of structure and enclosure but can also be the primary attraction. Some plants
can draw you outdoors at midday to watch butterflies and hummingbirds flit among your flowers. The fragrance of
an evening-blooming vine can entice you outside after dusk. The sinuous silhouette of a shrub can even lead you out
into the garden on a crisp winter afternoon.
The key to creating a garden sanctuary is to be sensitive to the use of space and design so that the plants and
materials have a unifying theme. Landscape elements can be added that fit with the theme and contribute to making
the garden more soothing or inspiring.
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