Poa annua – annual bluegrass weed

Annual bluegrass

If you take a close look at your lawn, you’re likely to find one of the most common weeds around: annual bluegrass, or poa annua. Annual bluegrass can cause headaches for golf fairway managers and homeowners who desire a smooth, manicured lawn. There are many types of annual bluegrass, both annual and perennial. This weed starts germinating around late summer, and is extremely difficult to control because it sends out lots and lots of seeds. It forms fibrous roots, dense clumps and can grow pretty tall, over a foot in height.

It’s difficult to control to remove, because it grows in turf, and can often outcompete other warm-season grass seeds. Poa tends to thrive when you mow your lawn too short, when you water lightly and too often and when you overfertilize. So the best way to control annual bluegrass is to keep a healthy turf. Washington State University Extension recommends maintaining a healthy turf area to prevent weed establishment, cultivation (tilling or hoeing to eliminate plants), hand pulling weeds, and careful digging as select non-chemical management options as your first choice.