Annual Bluegrass
Poa annua · Cool-season, Annual (sometimes short-lived perennial), C3
Grass Family
Poaceae, Pooideae, Tribe Poeae
Grass Category
Invasive/Weed Grass, though sometimes managed on Golf Course Greens
Variety / Cultivar
Common Poa annua (ecotype varies by climate)
Hardiness Zones
USDA Zones 3-10; highly cold tolerant but often dies out during summer heat/drought stress.
About This Grass
A low-growing, light green tufted grass that stands out from darker turf. It produces prolific, whitish branched seed heads even at very low mowing heights of 0.125 inches.
Blade Characteristics
Fine to medium width (2-3mm), flat or slightly V-shaped, with a distinctive boat-shaped tip. Typical light apple-green color with folded vernation and a prominent membranous ligule.
Root System
Shallow, fibrous root system; lacks deep drought resistance; very fast establishment from seed and poor thatch formation.
Growing Information
Origin Region
Native to Europe and Eurasia, now naturalized worldwide in temperate climates
Growth Habit
Bunch-type/clump-forming, occasionally developing short stolons in certain biotypes
Sunlight & Water Needs
Full sun to partial shade; prefers high moisture and frequent irrigation; thrives in compacted, wet soils.
Mowing & Maintenance
Highly adaptable; can survive heights from 0.1 to 4 inches; high maintenance if managed as turf; requires high nitrogen and specific herbicide programs if being suppressed.
Special Characteristics
Extremely high seed production; can produce viable seeds only days after flowering; low wear tolerance compared to perennial turf grasses.
Ecological Information
Commonly considered a major weed in lawns and golf courses; provides minimal value to wildlife except as incidental forage for some insects; highly invasive in disturbed sites.