Annual bluegrass

(More Lawn Weeds)

Annual bluegrass
Poa annua

Annual blue grass going to seed

Closeup of flower stalk

Life cycle

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 In Lawns

• Cultural practices
  Maintain healthy, dense turf that can compete and prevent weed establishment.
  
  
• Mechanical Management
  Hand pulling or using an appropriate weeding tool are the primary means of mechanical weed control in lawns. Clumps can also be dug out. 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.

• Chemical Treatment/Prevention in Lawns 
  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 preemergent products are also labeled for Poa annua so check the label. Annual bluegrass research shows that the plant is becoming resistant to the preemergent Barricade (Prodiamine). Check the labels of Dimension (Dithiopyr) and Halts (Pendimethalin) for information on Poa annua control.
  
  
  
• Organic Lawn Herbicides