annual bluegrass USDA PLANTS Symbol: POAN
U.S. Nativity: Exotic
Habit: Grass or Grasslike
Poa annua L.

Jump to: Images | Distribution Maps | Sources
Taxonomic Rank: Liliopsida: Cyperales: Poaceae
Synonym(s): annual blue grass, walkgrass
Native Range: Uncertain - prob origin Europe (GRIN);

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.

Selected Images from Invasive.orgView All Images at Invasive.org


Flower(s); inflorescence.
Joseph M. DiTomaso, University of California - Davis, Bugwood.org
Additional Resolutions & Image Usage

Stem(s);
Bruce Ackley, The Ohio State University, Bugwood.org
Additional Resolutions & Image Usage

Foliage;
Joseph M. DiTomaso, University of California - Davis, Bugwood.org
Additional Resolutions & Image Usage

Flower(s);
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Plant(s);
Bruce Ackley, The Ohio State University, Bugwood.org
Additional Resolutions & Image Usage

Plant(s);
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Floret(s); Floret in lateral view.
D. Walters and C. Southwick, USDA, Bugwood.org
Additional Resolutions & Image Usage

EDDMapS Distribution:
This map is incomplete and is based only on current site and county level reports made by experts and records obtained from USDA Plants Database. For more information, visit www.eddmaps.org
 


State(s) Where Reported invasive.
Based on state level agency and organization lists of invasive plants from WeedUS database.

U.S. National Parks where reported invasive:
Death Valley National Park (California)
Fort Bowie National Historic Site (Arizona)
Haleakala National Park (Hawaii)
Yellowstone National Park (Wyoming)



Invasive Listing Sources:
California Invasive Plant Council
City of Ann Arbor Michigan Parks and Recreation
Georgia Exotic Pest Plant Council
Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
Kentucky Exotic Pest Plant Council