Weed of the Week: Annual Bluegrass

Written by: Aly Shinkle, Jason Bond and Tom Eubank

Annual Bluegrass
Family: Poaceae
Scientific name: Poa annua (L.)
Synonyms: Poanna, Poa

Photo: Univ. of Arkansas Division of Agriculture

Annual bluegrass is a cool-season annual grass, is relatively small (3 to 12 inches tall), grows in dense clumps, and frequently roots at the lowest nodes. The leaf blades are hairless and boat-shaped near the tip. The plant has a membranous ligule that is slightly pointed, and the seedhead is an open panicle that has a triangular pattern with approximately eight flowers per spikelet.  Characteristic identifying features are its light green color, low and clumping growth habit, open leaf sheath, and lack of hairs.

Annual bluegrass is native to Europe but is found throughout the United States and Canada.  It is common in Mississippi from fall through spring on commercial and residential lawns, golf courses, roadsides, pastures, and cultivated fields. It is particularly problematic on golf course greens and fairways because of its low growth habit.  Depending on the habitat, annual bluegrass can be an unsightly and problematic weed that is hard to control in uniform turf.  Annual bluegrass has been confirmed resistant to glyphosate in Missouri and Tennessee.

Bryson, C.T. and M.S. DeFelice. 2009. Weeds of the South. Athens, GA: University of Georgia Press. pp.405.

Virginia Tech Weed Identification Guide.  http://www.ppws.vt.edu/scott/weed_id/brote.htm

University of Arkansas Division of Agriculture.  http://www.aragriculture.org/horticulture/ornamentals/weed_id/bluegrass_annual.htm

Photo: Virginia Tech Weed ID Guide