Annual Bluegrass
Poa annua · Cool-season, Winter Annual (sometimes short-lived perennial), C3
Grass Family
Poaceae, Pooideae, Tribe Poeae
Grass Category
Invasive/Weed Grass (often found in Lawn/Turf and Golf Course Greens)
Variety / Cultivar
Not a specific cultivar; commonly identifies as 'Poa annua var. annua' for the bunch-style annual form.
Hardiness Zones
USDA Zones 3-10; survives winter under snow but dies off quickly during hot, dry summer heat.
About This Grass
A light-green, low-growing clumping grass. It typically grows in small, dense tufts and turns yellowish-green. It is most famous for producing prolific, whitish seed heads even when mowed very low.
Blade Characteristics
Fine to medium width; soft texture; light green color; folded vernation; prominent boat-shaped tip; crinkled or transverse wavy lines often visible on leaf blade mid-section.
Root System
Shallow, fibrous root system; lacks significant drought tolerance; forms a weak sod that is easily pulled from the soil.
Growing Information
Origin Region
Europe; long ago naturalized throughout North America and temperate regions worldwide.
Growth Habit
Bunch-type (clumping), though some perennial types can be slightly stoloniferous; low-growing and prolific seed producer.
Sunlight & Water Needs
Full sun to heavy shade; prefers moist to over-watered soils; very low drought tolerance; thrives in compacted, damp areas.
Mowing & Maintenance
0.125 to 2.0 inches; can survive extremely low mowing heights (golf greens). High maintenance as a weed because it requires frequent pre-emergent control to prevent spread.
Special Characteristics
Prolific seed production (can produce 360 seeds per plant); highly shade tolerant; salt tolerant; very poor heat/drought recovery.
Ecological Information
Introduced/Invasive; provides minor forage for some birds but generally disrupts the uniformity of managed turfgrass ecosystems.