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annual bluegrass

Poa annua L.

USDA PLANTS Symbol: POAN
U.S. Nativity: Exotic
Habit: Herb


Synonym(s): annual blue grass, walkgrass

Appearance
Poa annua is an erect or clump-forming annual grass that tolerates close mowing, or may reach 11 in. (27.9 cm) in height. It can also be identified by having light green grass with a boat-shaped leaf tip that resembles other lawn and turf grass species. This weed is very similar to Kentucky Bluegrass (Poa pratensis), but is much lighter in color and lacks rhizomes.
Foliage
Leaves are light green in color, especially when compared to the dark green color of other closely related turfgrass species (for example Kentucky Bluegrass, Poa pratensis). Leaf blades are 0.5-5 in. (1.3–12.7 cm) long, 0.04-0.2 in. (1-5 mm) wide, folded in the bud and lack hairs on either surface.
Flowers
The seed head is an open panicle, 0.75-2.5 in. (1.9-6.4 cm) long, and pyramidal in outline.
Fruit
Fruit is an achene.
Ecological Threat
Poa annua is primarily a weed of lawns and turfgrass, found throughout the United States.