P&PDL Picture of the Week for
April 28, 2008

Annual bluegrass (Poa annua) is in bloom and setting seed

Glenn Hardebeck, Turfgrass Research Agronomist, Department of Agronomy, Purdue University

Annual bluegrass has long been a problematic grassy weed in high maintenance turf areas such as golf course greens, tees and fairways. In recent years, annual bluegrass has emerged as a lawncare problem as well. Annual bluegrass, as its name implies, is an annual grassy weed. It thrives in the spring and fall but suffers severely in the heat of the summer. Prolific seed production allows annual bluegrass to invade new voids or reinfest bare areas which were previously annual bluegrass before the summer heat set in. Currently, annual bluegrass is blooming and setting seed making it very easy to identify this light green grassy weed. Control is more difficult than identification. In some situations, managing annual bluegrass is actually more practical than attempting to control it. More information can be found at AY-41-W: ID and Control of Annual Bluegrass and Rough Bluegrass in Lawns (pdf file)

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Purdue Plant & Pest Diagnostic Lab Purdue Cooperative Extension Service