Bluegrass Annual

Bluegrass, Annual

Common Name: Bluegrass, Annual
Latin Name: Poa annua
Common Family Name: Grass Family
Latin Family Name: Poaceae = Gramineae

Other Names: Poa, walkgrass

Origin: Native to Europe, but one of the most widely distributed weed grasses in the United States. It thrives in turf, gardens, crops, roadsides, or any other open area.

Biology: An annual grass, with seeds germinating from late summer, through the winter, and into the following spring. Plants mature from late spring to early summer. Grows well in turf, where it outgrows the desirable turf creating a light green discoloration with abundant seedhead production, and when it dies in the summer it leaves a brown area on the turf.

Identification: Mature plants may be 1 foot tall and bright green. Reproduces only from seed, so stems grow from central point at the soil. Leaves are 2 to 3 inches long, hairless and soft, with ripples or crinkles commonly found near the center of the blade. Seed head may be 1 to 6 inches long with spreading branches which themselves may branch again. Seed heads are flattened and short, with only 3 to 6 seeds per cluster.

Characteristics Important in Control: May be a common weed in turf seed farms, resulting in turf seed contaminated with the Poa seeds. Germinates early and grows throughout the winter, dying out as hot season sets in. Easily adapts to mowing of turf, and will easily produce seed-heads even when mowed regularly. High fertility and irrigation encourage the growth of annual bluegrass.

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Chemicals exhibiting activity against this weed

Always refer to the product label for specific information on proper product use, tank-mix compatibility, and turfgrass tolerance. Products containing more than one of the chemicals listed below may offer improved control.

Season Emergence Chemical
Cool Pre Benefin, bensulide, dithiopyr, oryzalin, oxadiazon, pendimethalin, prodiamine
Post Bispyribac-sodium, ethofumesate
Warm Pre Benefin, bensulide, dithiopyr, fenarimol, napropamide, oryzalin, oxadiazon, pendimethalin, prodiamine
Post Atrazine, bispyribac-sodium, clethodim, diquat, ethofumesate, flazasulfuron, foramsulfuron, glyphosate, pronamide, rimsulfuron, trifloxysulfuron

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