A Quick Reference Guide to Some Common Invasive Grasses in

A Quick Reference Guide
to Some Common Invasive Grasses
in Central Florida
By Chris Matson and Lindsay Root, Illustrations Lindsay Root
Copyright © 2009 The Nature Conservancy
All Rights Reserved
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COGONGRASS – Imperata cylindrica
found everywhere except deep open water
colonial plant, small to big patches
light green, stand out from palmetto and other grass when backlit
flower spikes are singular per stem, narrow and silky, cotton candy like
HOW TO ID
o Asymmetrical midrib that is white/light
o Widest point on leaf is closer to tip than base
o Upright and stiff leaves, can be waist high
o Rough when rubbed from tip tobase of the
leaves
BAHIAGRASS – Paspalum notatum
- found along roadsides and pastures
- low growing, sod-forming
- toe to ankle high leaves, flowers/seeds knee high
- HOW TO ID
o pink roots (rhizomes)
o two pronged seed head, sometimes three, little or no hair on flowers/seeds
o leaves are pointy and can be hairy
- Similar species:
other Paspalums have slightly different
leaves
Carpetgrasses have boat-tipped leaves and
lots of hair on margins and/or midribs
Beaked panicgrass (Panicum anceps) does
not have strikingly pink rhizomes, and has
hair on leaves and sheaths often.
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VASEYGRASS – Paspalum urvillei
found in wet, or grass/sedge dominated areas
tall plant, 2.5-6 feet
forms colonies of bunches or scattered bunches
HOW TO ID
o Fuzzy flowers/seeds in simply branched spike at the top of the stem
o Leaves medium long, largely hairless, widest point is nearer tip than the
base
o Wavy or wrinkly pattern on a portion of the edge of the leaf
o Midrib is stiff from the base to about 1/3 length of the leaf
o Hairy at the base of a leaf
GUINEAGRASS – Panicum maximum
- found in disturbed areas where introduced by people
- large leaves, bunch forming
- stems with chest to knee high leaves
- HOW TO ID
o Tall openly branching flower/seedheads, rise
above leaves, 4-7 feet tall
o Flat, bright, smooth green leaves
- Looks most like switchgrass (Panicum virgatum) which
has pointed spikelets, Johnsongrass (Sorghum
halepense) which has much larger spikelets and awns
on spikelets are common, and fall panicgrass (Panicum
dichotomiflorum)which has distinctly zigzag stems, lateral stems creeping along
ground.
BERMUDAGRASS – Cynodon dactylon
- found in disturbed areas and near golf courses
- toe to ankle high, flowers shin height
- creeping and low lying
- HOW TO ID:
o Mat of grass, creep out of central point
o Leaf blades very narrow and blue-green, less than 4 inches long
o Flower/seed spikes radiate from stem in groups of 2-6, usually around 4,
and are about 0.5-2 inches in length from the center point.
- Look alikes:
o Crabgrasses (Setaria species) are usually hairy and much bigger-leaved
with long flower spikes (3-5 inches)
o Carpetgrases (Axonopus species) are much bigger leaved
o Low panicgrasses (Dichanthelium species) have a panicle rather than
forked spikes and many have broader leaves and are generally bunchformers rather than creeping, continuous mats.
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LIMPOGRASS – Hermarthria altissima
found in disturbed, wet, grassy areas
colonial grass with lots of stems
grows densely about waist to head high
HOW TO ID:
o Lot of reddish/purplish stem color can be present
o Leaves are green or spent-brownish
o Stems creep laterally along the ground
o Small fine leaves, droopy,
o Seeds stacked, resembles a backbone
Looks most like closely related jointtailgrasses (Coelorachis species) which are
uncommon to rare and are mostly bunch forming rather than big colonies of
rhizomatous tangles. Looks vaguely similar to Kissimmeegrass (Paspalidium
geminatum), which is only ankle to waist high and has broad stems, narrow
leaves and an
ascending habit
to each thick
stem. See also
torpedograss for
comparison.
ROSE NATALGRASS – Rhychelytrum repens
- found in dry, sandy, or gravelly areas, along roadsides and along levees
- clump forming
- ankle to above knee height
- HOW TO ID:
o Frosty blue-green hue is common in fresh growth
o Early basal sheaths and leaves turn burgundy then die
o Leaf blades flat, hairs on the top of blade and not hairy on the bottom
o Fluffy seed heads, silky pink and purple, flowers/seeds are branched
- Look-alikes include lovegrasses (Eragrostis species) which do not have fuzzy
spikelets, instead having multiple florets on each spikelet which look like
feathers superficially.
- TORPEDOGRASS – Panicum repens
- found in low competition disturbed sites in a variety of open grassy settings and
in the edges of marshes and cypress domes
- colonial grass
- HOW TO ID:
o Flower/seed spike branched at the top of stem
o Leaves are bluish green, blades narrow, linear, stiffly ascending usually
folded lengthwise rather than flat
o Stems rigid and round, lean at base, ascending to sometimes upright, toe to
knee high
o Spread via horizontal stems, spreads in lines at the edge of a colony
o Hairs on leaves lower on stem, hairiest where leaf meets the stem
- Look-alikes include Paspalum distichum which has a forked inflorescence and
floppier leaves, blue maidencane which does not normally have a distinct midrib
and has a hairs detectable on leaf margins by backlighting and usually wider,
darker leaves. Cutgrass (Leersia hexandra) has leaves that flop over and very
thin stems relative to
leaf width. See
limpograss above
for comparison,
also. Some
lovegrasses have the
same color but are
bunch-forming
grasses not colonial
and they have
multiple florets on
each spikelet rather
than a single floret.
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WRIGHT’S NUT-RUSH – Scleria lacustris, a sedge,not a grass
found in disturbed marsh, seasonally wet pastures, gumpond edges, road ditches,
edges of cypress wetlands
plants are tall from July to November
HOW TO ID:
o Distinctly triangular stems, very thick/fleshy
o Extremely rough leaves when stroked upward (beware can draw blood)
o Strongly striped leaves with red nerves at base
o Cross section of leaves resemble a W or M, and are relatively blunt or
rounded at the tip
o Nutlets turn from brown-green to pale-green to white and are BB sized
Look-alikes are all other nut-rushes (Scleria species) which are not so large,
broad-leaved or dangerously rough.