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Annual bluegrass (Poa annua)

Annual bluegrass Synonyms: Poa annua L. var. aquatica, Poa annua L. var. reptans

Common Names: Annual meadowgrass, annual wintergrass

Description: Cosmopolitan grass listed as one of the most aggressive weeds invading areas from sea level up to 1200 m in elevation.

Habit: Winter annual, clump-forming fast-growing annual and perennial type grass.

Leaves: Flat, slightly keeled, smooth, abruptly contracted at the apices, boat-shaped tip. Transversely wrinkled and folded into the sheath. Ligule is membranous and usually 2-3 mm.

Stems: Sometimes erect but usually geniculate and rooting at the nodes.

Flowers: Culms are smooth, erect, usually 10-20 cm. tall, solitary or paired branches. Spikelets are 3-5 mm long, lanceolage with 3-5 florets. Glumes are boat shaped with lower ones reaching 1.5-3 mm long and 1 vein and the upper 2-4 mm long with 3 veins.

Fruit and seeds: Achene

Habitat: Native to Eurasia. Can be found growing in moist, shady areas and in a wide variety of soils. Common in gardens, lawns, pastures, golf courses, urban parks, stream and lake margins, roadsides and disturbed areas.

Reproduction: By seed. Capable of producing 1050-2250 seeds that are dispersed by wind, water or animals, livestock and vehicles.

Similar species: Kentucky bluegrass (Poa pratensis).

Monitoring and rapid response: Does not appear to have a wide range of pests or parasites. Primary method of control is to prevent new infestations by removal of solitary plants.

Credits: The information provided in this factsheet was gathered from CABI: Invasive Species Compendium and UC IPM.

Individual species images that appear with a number in a black box are courtesy of the network ( photo author credits may not be included due to the small display size of the images and subsequent difficulty of reading the provided text. All other images appear courtesy of Google (

Common Name:

Annual bluegrass

Scientific Name:

Poa annua







USDA Symbol: