Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf
Variety / Cultivar
Standard turf-type cultivar (e.g., 'Midnight' or general blends)
Hardiness Zones
USDA Hardiness Zones 3 to 7, thriving in northern and transition zones. Excellent cold tolerance, goes dormant in extreme heat.
About This Grass
Forms a dense, high-quality turf with medium-fine texture and a rich dark green to blue-green color. Reaches 18 to 24 inches if unmoved, but is maintained at 1.5 to 2.5 inches. Produces open, pyramidal panicle seed heads at maturity.
Blade Characteristics
Medium-fine width (2-4mm), flat to folded shape with distinctive boat-shaped tips. Dark green to blue-green color. Folded in the bud (vernation). Features prominent parallel veins and a slight keel. Short membranous ligule with no auricles.
Root System
Moderately deep fibrous root system with extensive underground rhizomes. Moderate to high thatch-forming tendency depending on management. Slow to moderate establishment speed from seed, but recovers well from damage via rhizomes.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America and cool-temperate regions worldwide
Growth Habit
Rhizomatous, spreading underground via aggressive horizontal shoots to form a dense sod
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily) for best performance, with moderate to high water needs. Good cold tolerance but enters semi-dormancy during severe summer heat and drought.
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.5 inches. Requires regular mowing, medium-high fertilization (3-4 lbs N per 1000 sq ft annually), periodic dethatching, and aeration. Maintenance level is Medium to High.
Special Characteristics
High wear and traffic tolerance due to aggressive rhizomatous spreading. Good cold hardiness, moderate shade tolerance, and excellent recuperative ability. Prone to summer patch and dollar spot if improperly managed.
Ecological Information
Introduced species in North America. Provides moderate wildlife habitat and excellent soil stabilization and erosion control due to dense sod formation. Frequently blended with perennial ryegrass and fescues.