annual bluegrass
(Poa annua L.)

Overview

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

Maps

Invasive Listing Sources

• Alaska Noxious Weeds
• Georgia Exotic Pest Plant Council - Category 3
• Invasive Plant Species of West Virginia
• Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
• Kentucky Exotic Pest Plant Council - Moderate Threat
• Maryland Code and Regulations Noxious Weed & Seed Law
• National Park Service, Mid-Atlantic Exotic Plant Management Team Invasive Plant List
• Nonnative Invasive Species in Southern Forest and Grassland Ecosystems
• Pacific Northwest Exotic Pest Plant Council, 1998
• WeedUS - Database of Plants Invading Natural Areas in the United States
• West Virginia Native Plant Society, Flora West Virginia Project, and West Virginia Curatorial Database System, September 3, 1999

References