Identifying Common Pennsylvania Grasses

Grass identification tips and techniques.
Identifying Common Pennsylvania Grasses - Articles

Updated: August 8, 2017

In This Article
Identifying Common Pennsylvania Grasses

Recommended if ligule or auricle are unfamiliar words.

Awn: a bristle characteristic of the spikelets in some grasses.

Internode: Area of the stem between two nodes.

Node: A joint where a leaf is or was attached to a stem.

Rhizome: A stem that grows horizontally below the ground surface and may form adventitious roots at the nodes.

Stolon: A stem that grows horizontally above the ground surface and may form adventitious roots and a new plant at the nodes.

Recommended if you are familiar with grass structures.

Common Grasses Found in Pennsylvania Hay and Pasture Fields
Grass
Species
Life Cycle
Plant Height
SheathBladeCollarAuriclesLiguleStemInflor-
escence
Comments
Barnyard grass Echinochloa muricata Beauv.Annual
1-3 ft
Over-
lapping
1-15mm wide. Flat with rough edges.
BroadNoneNoneRound and branching at nodes.
Panicle of spike-like branches.
Found in late summer/ early fall. Seed structures purplish and covered with short stiff bristles.
Bermudagrass
Cynodon dactylon L.
Perennial/
Annual
1-2 ft
Papery8-15 mm wide. Hairy on top and bottom.
Narrow
NoneFringe of hairs
Prostrate and upright
3-7 spiked branches originating from a single whorl.
Spreads by both stolons and rhizomes. Found as a perennial only in very southern PA and further south.
Big Bluestem
Andropogon gerardii Vitman
Perennial
7-9 ft
Split, hairy
10-14mm wide. Smooth with fringe of hairs at junction of blade and sheath.
NarrowNone
Short membrane
Round and upright
Raceme, red in color.
Stems purplish at base. Awns in seed clusters makes inflo-rescence look hairy.
Crabgrass (Large)
Digitaria sanguinalis L.
Annual
2-3 ft
Over-
lapping
5-12 mm wide. Rough edges with hairs on both sides. Red-purple color.
Broad and divided
NoneMembrane. Rounded at top
Upright to prostrate
3-10 spiked branches in whorls at top of stem.
Found in late summer/ early fall.
Crabgrass (Smooth)
Digitaria ischaemum L.
Annual
1-2 ft
Over-
lapping
5-12mm wide with no hairs on either side. More purplish than Large Crabgrass
Broad and dividedNoneMembrane. Rounded at topUpright to prostrate3-10 spiked branches in whorls at top of stem.Found in lawns or heavily grazed pastures in late summer/ early fall.
Fall panicum
Panicum dichotomiflorum Michx.
Annual
1-4 ft
Over-
lapping
10-20 mm wide. Smooth or sparsely hairy near base
BroadNone
Fringe of hairs
Upright to prostrate
Fine, wide-
spreading panicle
Found in late summer/ early fall.
Giant foxtail
Setaria faberi.
Annual
3-6 ft
Over-
lapping. Edges are hairy
10-20 mm wide. Hairy on top and smooth on bottom.
Broad and hairy on edges
NoneFringe of hairs
Round and upright
Spike-like panicle, bristly, drooping
Inflo-rescence bushy like a fox's tail. Hairy blade is key to identification.
Green foxtail
Setaria viridis L.
Annual
1-3 ft
Over-
lapping. Edges are hairy
5-12 mm wide. Not hairy on top or bottom.
Broad and sometimes hairy
NoneFringe of hairs
Round and uprightSpike-like panicle, bristlyInflo-rescence bushy like a fox's tail and slightly purple in color. No hairs on leaves.
Italian ryegrass
Lolium italicum Parn.
Annual to Perennial
1-2 ft
Over-
lapping
2-6 mm wide. Flat and pointed at tip. Waxy.
May be divided
OverlappingMembrane. Rounded at top
Round-to-flat
Slender stiff spike with awns.
Bunchgrass with waxy leaves that are shiny. Spikelet edge against stem.
Kentucky bluegrass
Poa pratenis L.
Perennial
1-2 ft
Split2-5 mm wide. Boat-shaped tip.
BroadNoneVery short membrane.
Round-to-flatFine pannicle
Sod-grass (short rhizomes) dark green. Invades overgrazed pastures.
Nimblewill
Muhlenbergia schreberi Gmel.
Perennial
1-2 ft
Split and over-
lapping
2-4 mm wide. Rough on top with hairs behind ligule.
NarrowNoneShort membrane
Mostly prostrate
Many fine, slender panicles.
Sod-forming (stolons). Flowers in late summer to early fall.
Orchardgrass
Dactylis glomerata L.
Perennial
1-3 ft
Split5-12 mm wide. V-shaped at base, flat and pointed at tip.
Broad and divided
NoneWhite membrane, pointed at top
Flat
Course panicle.
Bunchgrass. Light green in color.
Perennial ryegrass
Lolium perenne L.
Perennial
1-2 ft
Over-
lapping
2-6 mm wide. Folded in shoot V-shapped, Waxy
Narrow, may be divided
ShortMembrane, toothed at top
Round-to-flatSlender stiff spike. No awns.
Short growing bunchgrass with waxy leaves that are shiny. Spikelet placed with edge against stem.
Quackgrass
Elytrigia repens.
Perennial
1-3 ft
Over-
lapping with hairs
5-10 mm wide. Slightly hairy on upper surface.
Broad and dividedLong-
clasping
Short membrane
RoundSlender stiff spike
Sod forming with prominent fast spreading rhizomes. Spikelet flat against stem.
Red top
Agrostis gigantea Roth
Perennial
1-3 ft
Over-
lapping
2-7 mm wide. Flat.
Broad and V-shaped.
NoneTall membrane
RoundPanicle. Rust colored at maturity.
Sod-grass (short rhizomes). Prominent ridges on upper surface of blade.
Reed canarygrass
Phalaris arundinacea L.
Perennial
1-6 ft
Over-
lapping
10-20 mm wide. Flat with rough edges.
Narrow and continuous. Yellow.
NoneProminent membrane
RoundPanicleSod forming (prominent rhizomes.)
Smooth bromegrass
Bromus inermis L.
Perennial
1-3 ft
Closed
4-12 mm wide. Flat and pointed at tip.
Narrow and divided
NoneShort membrane
RoundLarge panicle, often drooping
Young plants may have pubescence on sheath. Rhizomes covered with brown papery scales.
Switchgrass
Panicum virgatum L.
Perennial
3-8 ft
Split, with hairy margin
7-14 mm wide. Hairy on top.
Broad, often with hairs.
NoneFringe of short hairs
Round and upright
Large panicle
Leaves covered with hairs. Spreads by rhizomes.
Tall Fescue
Festuca arundinacea Schreb.
Perennial
1-3 ft
Over-
lapping
5-10 mm wide. Dark green. Very rough edges
Broad and divided. Wrinkled on edges
Blunt with few hairs
Short membrane
RoundSpreading panicle
Bunchgrass. Prominently veined, leathery, dark green leaves with rough edges.
Timothy
Phleum pretense L.
Perennial
2-3 ft
Over-
lapping
4-12 mm wide. Flat and pointed at tip
Broad and continuous
NoneWhite membrane with two notches
RoundSpike-like panicle
Bunchgrass with corms (onion-like bulb at base of stem)
Witchgrass
Panicum capillare L.
Annual
1-3 ft
Over-
lapping
8-15 mm wide. Hairy on top and bottom
Narrow
NoneFringe of hairs
Round and uprightLarge panicle
Leaves covered with hairs. Large panicle often breaking off of stem.
Yellow foxtail
Setaria glauca.
Annual
1-3 ft
Over-
lapping, not hairy
5-10 mm wide. Hairy only on top near base of blade.
Broad and hairy on edges
NoneFringe of hairsRound and uprightSpike-like panicle, bristly
Inflo-
rescence is bushy like a fox's tail. Hairs only on upper surface of blade near base.

Glossary

Annual: A plant that completes its life cycle and dies within a year.

Awn: A bristle characteristic of the spikelets in some grasses.

Bunchgrass: Plant has no stolons or rhizomes and consequently grows in a bunch rather than spreading.

Inflorescence: Flower structure of a grass plant.

Node: A joint where a leaf is or was attached to a stem.

Panicle: A type of flower in which the flower clusters are attached to the stem via branches connected to branches off the stem.

Perennial: A plant that lives through three or more seasons.

Prostrate: Growing flat along the ground.

Raceme: A type of flower in which the flower clusters are attached to the stem via branches.

Rhizome: A stem that grows horizontally along the ground surface and may form adventitious roots at the nodes.

Sheath: Base portion of the grass leaf that wraps around the stem.

Spike: A type of flower in which the flower clusters are attached directly to the stem.

Stolon: A stem that grows horizontally along the ground surface and may form adventitious roots and a new plant at the nodes.