Annual Bluegrass
Poa annua · Cool-season, Winter Annual (sometimes short-lived perennial), C3
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Invasive/Weed Grass, Golf Course Grass (when managed as greens)
Variety / Cultivar
Native/Wild type (Poa annua var. annua)
Hardiness Zones
USDA Zones 3-10; thrives in cool/moist weather and often dies out or goes dormant in extreme summer heat.
About This Grass
A low-growing, bright yellowish-green grass often found in disturbed areas or lawns. It has a characteristic clumped appearance with prolific seed production even at very low heights. Texture is soft and fine to medium.
Blade Characteristics
Fine to medium width (2-3mm), folded vernation, boat-shaped tip, light green color, smooth texture with a prominent midrib, membranous ligule, no auricles.
Root System
Shallow fibrous root system; lacks significant rhizomes or stolons; establishes very quickly from seed; poor drought tolerance due to depth.
Growing Information
Origin Region
Native to Europe and Eurasia; naturalized globally in temperate climates
Growth Habit
Low-growing, bunch-type to slightly spreading, can form small dense clumps/mats
Sunlight & Water Needs
Full sun to heavy shade; high water requirement; prefers moist, fertile, compacted soils; very low drought tolerance.
Mowing & Maintenance
0.5 to 2.0 inches; high frequency; requires high nitrogen to maintain aesthetics; often considered a weed to be eradicated in high-end turf.
Special Characteristics
Highly prolific seeder; can produce seed heads at mowing heights as low as 0.1 inch; poor heat and drought tolerance; excellent shade tolerance.
Ecological Information
Introduced/Invasive in most regions; provides minimal wildlife value; often outcompetes desirable turf species in wet, shady, or compacted areas.