Annual Bluegrass
Poa annua · Cool-season, Annual (sometimes short-lived perennial), C3
Grass Family
Poaceae, subfamily Pooideae
Grass Category
Invasive/Weed Grass, Lawn/Turf weed
Variety / Cultivar
Wild type / common biotypes
Hardiness Zones
USDA Hardiness Zones 2 to 10, highly adaptable to cool and mild climates but struggles with extreme summer heat
About This Grass
Low-growing, light green turf weed that forms pale patches in lawns; grows rapidly and produces abundant seed heads even when mowed very low; height ranges from 2 to 12 inches when unmowed; fine to medium texture with distinctive whitish-green seed heads shaped like small panicles
Blade Characteristics
Blades are 1 to 4 mm wide, flat or folded, with characteristic boat-shaped tips; light green to yellowish-green color; vernation is folded; ligule is membranous and prominent; auricles absent
Root System
Shallow, fibrous root system with weak drought tolerance and rapid seed-to-seed lifecycle; does not form a durable dense sod
Growing Information
Origin Region
Europe and Eurasia, now globally distributed in temperate and subtropical regions
Growth Habit
Bunch-type to loosely spreading, spreading by seed rather than aggressive rhizomes
Sunlight & Water Needs
Thrives in full sun to partial shade, especially in moist or compacted soils; prefers frequent moisture and has poor drought tolerance, entering summer dormancy quickly
Mowing & Maintenance
High maintenance weed; tolerates very low mowing but continuously produces seed heads below standard mower blade heights; difficult to control selectively in turf
Special Characteristics
Very low traffic tolerance, poor drought resistance, highly prolific seed producer, often considered a troublesome weed in fine turf and golf course putting greens
Ecological Information
Introduced weed species globally; provides minimal ecological value as a lawn weed; easily colonizes disturbed soils, bare spots, and over-watered turf areas