Woodland Tree Herbaceous Intersectional

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lecture notes -
The Kings and Queens of Flowers
Peonies are native throughout the northern hemisphere and have been cultivated for centuries both in Europe and Asia. They are
classified into twenty five species in four subgenera, Halda & Waddick (2004). The science is somewhat fluid, with the promotion
and demotion between species and subspecies being a relatively common occurrence. This presentation highlights: A) three species
of herbaceous peonies: P. officinalis, P. lactiflora, and P. obovata, subspecies japonica; B) one species of tree peony P. suffruticosa
along with a subspecies P. rockii; C) one group of hybrids commonly known as the Itoh peonies or more broadly as intersectional
peonies. In thinking about garden design, we will discuss these peonies in the following four groups: woodland, tree, herbaceous,
intersectional.
Tree
Herbaceous
Intersectional
Woodland
PEONIES: Kingdom Plantae | Division Magnoliophyta | Class Magnoliopsida | Order Saxifragales | Family Paeoniaceae | Genus Paeonia
Types of Peonies In Order of Bloom
Woodland Herbaceous Peonies are a separate species of herbaceous peonies worth noting individually due to their preference for
shade. Woodland peonies grow and naturalize in a deciduous woodland where they get the early spring sun and summer shade.
Each plant becomes eighteen inches tall and three feet in diameter. They seed creating sprays of low growing forest groundcover.
Woodland peonies provide three season appeal with white flowers in early spring, lush green foliage throughout the growing
season, and dramatic indigo and scarlet seed pods in the fall. Good naturalizers, easy to grow, deer proof plants.
Tree Peonies are woody perennial shrubs. They bloom at the beginning of May before the herbaceous peonies. Their woody
structure allows them to produce gigantic dinner-plate-sized flowers on plants that grow from 3 to 7 feet tall. After the bloom, tree
peonies provide structure to the garden with deep green leaves in summer and bronze and purple foliage in fall. Native to China
and cultivated for millennia, these deer-resistant plants thrive in horticultural zones 4-9. Tree peonies grow slowly, producing 1 to
6 inches of new growth each year. Given well-drained soil and dappled sunlight, they will live for centuries. Stately, rare, fabulous.
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Herbaceous Peonies are disease resistant perennial plants that enhance the structure and beauty of any garden and produce some
of the best cut flowers available. They bloom during the transition from spring into summer, with each individual cultivar
blooming for an average of 7-10 days. The foliage of shining green leaves remains throughout the summer, dies back to the ground
in winter and reemerges early each spring. Herbaceous peonies require very little care and live for generations. They have been
cultivated for centuries and can thus be found in an astounding array of flower form, color and fragrance. Herbaceous peonies can
be planted in both early spring and fall. They need at least 5 hours of full sun and rich well-draining soil. Like most long-lived
perennials it can take three years for them to bloom prolifically - they are well worth the wait. Mainstay in every perennial garden,
best cut flower available, deer proof.
Intersectional Peonies, also know as Itoh Hybrids, are a hybrid produced by crossing a tree peony with an herbaceous peony.
These peonies produce tree peony flowers and leaves on plants that behave like herbaceous peonies, dying down to the ground in
winter and reemerging each spring. One plant may produce 50 or more dinner-plate sized flowers on strong short stems that do
not require staking. They reach peak bloom near the end of the herbaceous peony bloom. Each plant can remain in bloom for 3-4
weeks. They can be used as cut flowers and offer an astounding array of yellows and golds -- colors not widely available in
herbaceous peonies. They are disease resistant, less susceptible to powdery mildew than their herbaceous parent and less susceptible
to botrytis blight than their tree peony parent. Dinner plate size flowers, easy to grow, deer proof.
flower color
Colors of Woodland Peonies
Peonies come in a multitude of colors. The colors available, and characteristics of that color,
depend on the type of peony.
pink
white
Colors of Tree Peonies
white
pink
coral
red
black
lavender
multi
green
yellow
copper
magenta
black
multi
green
yellow
red
coral
red
white
Colors of Herbaceous Peonies
white
blush
pink
Colors of Intersectional Peonies
yellow
pink
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copper
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Flower shape
single
lotus
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chrysanthemum
rose
hundred
proliferate
golden
circle
anemone
japanese
crown
bomb
Peony flowers come in ten flower forms from a simple daisy-like flower to a complex ball of petals. The more petals, the longer the
flower will bloom, but more petals means more weight and heavier flowers, and thus the need for support. Cultivars offering
lighter flowers, thus fewer petals, are sometimes labeled “landscape peonies” as they are easy to use in the landscape with little or
no support. Heavier flowers are old fashioned favorites, a mainstay of the perennial border and the cut-flower industry.
cultivar selection guide
woodland
Tree
Herbaceous
intersectional
selecting woodl and peonies
The shade loving woodland peony is commercially available as Paeonia obovata, the species, or Paeonia japonica, the subspecies.
Obovata is the pink form of the plant. It is taller and thus leggier than the subspecies P. japonica, which is a beautiful low growing
shade groundcover. They both naturalize well, have small single petaled flowers, and offer three season appeal. They have
interesting and colorful early spring foliage and fascinating vibrant indigo and scarlet seed pods in the fall. They are deer proof.
Peony’s Envy recommends planting Paeonia japonica as a ground cover and collecting Paeonia Obovata simply as a novelty plant.
For a naturalized planting of Paeonia japonica we begin by throwing the number of tennis balls that correspond with the number
of plants we want to plant up into the air loosely and allowing them to settle naturally. Then digging a hole at each location where
a tennis ball falls.
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selecting tree peonies
Consider: Dimensions | Leaf | Flower Posture | Bloom Time
Dimensions: Plant Height
Tree peonies can grow to be seven feet high, but most specimens even after decades remain between three and five feet. They are
classified as tall, mid, and dwarf with the potential to grow 7, 5 or 3 feet respectively. The milder the climate, the less winter die
back and the taller the potential of the plant. Tall varieties add five to six inches of new wood every year while dwarf varieties add
less than one. Taller varieties will make a bigger statement earlier in your garden; dwarf varieties can be planted as borders and
under windows.
7’
5’
3’
Tall
Dimensions: Plant Form/Shape
Mid
Dwarf
Tree peony bushes grow upright or more laterally. Typically, plant height and shape are associated. Taller varieties are upright and
dwarf varieties are spreading, but not in all cases. Conical varieties sacrifice some lower leaf coverage and need to be placed in the
garden accordingly.
Conical
Partially Spreading
Spreading
Leaf Type
Tree peony leaves provide beauty in the garden for three seasons. They leaf-out in early in April and provide spring, summer and
fall color. The size of the leaf varies from long and thin to big and round and can make a difference in the plant’s use in the
garden.
Long Thin
Medium
Round/Orbicular
Flower Posture
Tree Peony Flowers can be upright, lateral, or pendulous. Upright flowers are carried at the ends of stiff stems, well above the
leaves and grow at the top and sides of the bushes. Lateral flowers grow at the edge of the leaves. They are easy to see, but
concentrate themselves on the sides of the bushes. Pendulous flowers have short, flexible stems and hang down under the leaves.
Upright
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Lateral
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Pendulous
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Placement/Use
Anchor
Bookends
5’ wide circle
Grouping
5’ on Center
Walkway
Hedge
5’ on Center
Double Hedge
5’ on Center
5’ on Center
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selecting herbaceous peonies
Consider: Use| Flower Form | Height | Bloom Time
Use or Placement
Consider first what you are wanting out of your herbaceous peonies.
Plant Posture
Flower form and peony height influence the behavior of herbaceous peony plants. Traditional peonies, such as those that could
be found in your grandmother’s garden, were often bred to have long stems and huge full flowers. These enormous blossoms
produce some of the best cut flowers available. As garden plants these peonies tend to bend under the weight of the flowers and
require staking to remain upright. Plants with these characteristics include those of chrysanthemum, rose, golden circle, crown
and hundred proliferate flower forms and have innumerable dense petals. Lighter flower forms such as anemone, single, and
lotus tend to float above the plant, requiring far less support. However, due to their fewer number of petals these flowers do not
last as long in the hot sun nor are they the best cut flower varieties.
The necessary support for the herbaceous peony is determined by flower form and plant height. The shorter the plant the
sturdier the stems. The taller the plant the more support it will need. The most low maintenance garden plants tend to be
2.0-2.5’ anemone, single and lotus varieties. The best cut flowers tend to come from 3’ tall chrysanthemum, rose, golden circle,
crown and hundred proliferate shaped flowers.
Herbaceous peonies bloom at the transition between and summer. They grow in zones 3-8. Typically the bloom occurs in
mid-May in the southern zones, late-May in the mid zones and early-June in the colder zones. Basically all peonies will come at
the same time but there are slight variations in the timing dependant on the early, mid, late designation of the cultivar itself.
Further information on the bloom time of each cultivar please go online to the “Peony Date Project” done by Heartland Peony
Society.
Anemone
Single
Lotus
light flower forms
minimal staking needed
heavy flower forms
staking needed
Chrysanthemum
Rose
Golden Circle
Crown
Hundred Proliferate
Staking Options
Staking Options
Tomato Rings
Peony Rings
Tomato Rings
Peony Rings
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Fencing
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Fencing with Lattice Overlay
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Border Fencing
Placement/Use Herbaceous
Entryway
Accent Plant
Grouping
Accent Group
3’
18”
3’ wide circle
Walkway
18”
3’
1.5’
total area: 5 to 6’ equilateral triangle
3’
spacing for multiple peonies
3' wide
Row Planting
1.5'
total area 21' long
Double Row Planting
3’ tall
varieties
2.5’ tall varieties
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Border or Hedge Planting
aerial view of garden. Plants 3 feet on center
total area 39’ long
6’ wide
center of hole 1.5’ from outside edges of planting area
Walkway
aerial view of garden. Plants 3 feet on center
6’ wide
total area 39’ long
Pathway/Walkway
3’ wide
center of hole 1.5’ from outside edges of planting area
Cutting Garden
aerial view of garden.Plants 3 feet on center
total area 42’ long
total area 20’ wide
center of hole 1.5’
from outside edges
of planting area
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selecting intersectional peonies
Selection
Due to the relatively new hybridization of intersectional peonies the characteristics of plant height, shape, leaf coverage and
flower form tend to be fairly uniform. The choice of cultivar is then determined by color. It should be noted that intersectional
peonies have great leaf coverage from the base to the top of the plant and make excellent accent plants as well as function well at
the front of a border.
History
The group of peonies known as the Itoh or Intersectional peonies is a relatively new introduction. They are a hybrid produced by
crossing a tree peony with an herbaceous peony. Mr. Toichi Itoh of Japan is credited with being the first to do this successfully.
He crossed Paeonia x lemoninei , a hybrid tree peony, with P. lactiflora ‘Kakoden’, a white-flowered herbaceous peony. The tree
peony was used as the pollen parent, the herbaceous as the seed parent. The crossing produced 36 seedlings, nine of which had
dominant characteristics of tree peonies and became the first Itoh hybrids. Four of these seedlings, with permission from Mr.
Itoh’s widow, were patented by Louis Smirnow in the late 1960’s. The American Peony Society refers to this new group as the
Itoh Hybrids Group, but more widely the original four are the Itoh Hybrids and all subsequent hybrids are referred to as
intersectionals.
This group of plants is only now becoming widely available, coming down in price from up to 1,000 per plant in the late 1990’s
to less than 100 more recently. The leaves and flowers resemble tree peonies, but the foliage is herbaceous. One plant may
produce 50 or more dinner-plate sized flowers on strong short stems that do not require staking. They reach peak bloom after
herbaceous peonies, can be used as cut flowers and offer an astounding array of yellows and golds-- colors not widely available in
herbaceous peonies. They are disease resistant, less susceptible to powdery mildew than their herbaceous parent and less
susceptible to botrytis blight than their tree peony parent. Hybridization and cultivation methods continue to be active, with
Don Hollingsworth, Roger Anderson, William Seidl, and Don Smith all working in the field.
Original Toichi Itoh Hybrids - Introduced in the United States by Louis Smirnow in the late 1960's
P. 'Yellow Crown', P. 'Yellow Dream', P. 'Yellow Heaven', P. 'Yellow Emperor'
Placement/Use
Accent
Bookends
Walkway
3’ to 5’ wide circle
aerial view of garden. Plants 3 feet on center
total area 9’ long
Grouping
6’ wide
center of hole 1.5’
from outside edges of planting area
3’ to 5’ on Center
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Front of a Mixed Perennial Border
3’ to 5’ on Center
Intersectional Peony Border
Plant Intersectional
Peonies with Herbaceous Peonies
to extend the bloom
A. Herbaceous Bloom First
B. Intersectional Peonies Bloom Second
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References & Further Information
Peony References
www.peonysenvy.com
Carsten Burkhardt's Web Project Paeonia - http://www.paeon.de/
Seven Weeks of Bloom - http://bloomdate.paeonia.com
Page, Martin “2005” Paeonia Itoh Hybrid. New Plants. pp. 36-39
Lianying, Wang, et.al. 1998. Chinese Tree Peony, Beijing China. China Forestry Publishing House.
Chen, D. Z. & McLewin, W. (2006) Peony Rockii and Gansu Mudan. Wellseley-Cambridge Press Stockport, UK.
Peony Societies
American Peony Society - www.americanpeonysociety.org
Heartland Peony Society - www.peonies.org
The Peony Society-UK - www.paeonia.org
For information on peony planting, care and cut flowers
please visit www.peonysenvy.com and click on “Peony Care” at the top of the page.
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