University of Maryland Extension

Annual bluegrass

(More Lawn Weeds)  (Lawn Control Options)  

Annual bluegrass
Poa annua

flowering annual bluegrass
Annual blue grass going to seed

annual bluegrass flower stalk
Closeup of flower stalk

Lifecycle

Winter annual less than 1-ft. tall. Can die out in summer.

Growth habit

Bunching.

Reproduction

Seed; enlarges by tillering.

Conditions that favor growth

Cool, moist conditions; compacted soil; close mowing; high levels of nitrogen. Avoid overwatering and applying too much nitrogen fertilizer. 

Management

Cultural control: Maintain healthy, dense turf that can compete and prevent weed establishment.
Mechanical control: Hand pulling or using an appropriate weeding tool are the primary means of mechanical weed control in lawns. This is a viable option at the beginning of an infestation and on young weeds. Hand pulling when the soil is moist makes the task easier. Weeds with tap roots like dandelions or have a basal rosette (leaves clustered close to the ground) like plantain are easier to pull than weeds such as Bermudagrass (wiregrass) or creeping Charlie (ground ivy) that spread with stolons or creeping stems that root along the ground.
General chemical control: (lawn) Seeds germinate in late summer to early September. Control with a preemergent herbicide applied in mid-August/early September before the seeds germinate (sowing grass seed will not be possible). Some crabgrass preemergents are also labeled for Poa annua. Read product label to see if a second application is necessary and for information about watering and reseeding after application. 

Organic control

For a glossary of herbicide terms and additional information see: control options

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