Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
AI-generated identification · may be incorrect
Grass Category
Lawn/Turf Grass, Sports Turf
Hardiness Zones
Thrives in USDA Hardiness Zones 3 through 7. Excellent cold tolerance, surviving extreme northern winters, but experiences summer dormancy or stress in hot southern climates unless heavily irrigated.
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Variety / Cultivar
Midnight (known for deep dark green color and dense growth habit)
About This Grass
Forms a dense, high-quality turf with a rich, medium-to-dark green color. Unmowed height reaches 18 to 24 inches, but maintained lawns are kept low. Texture is fine to medium. Produces open, pyramid-shaped panicle seed heads at maturity.
Blade Characteristics
Fine to medium width (2-3mm), folded in the bud (vernation), with distinctive boat-shaped tips and parallel veins. Color ranges from medium to dark green or blue-green. Ligule is short and membranous; auricles are absent.
Root System
Moderately deep fibrous root system combined with extensive underground rhizomes. Moderate to high thatch-forming tendency under high fertility. Slow to moderate establishment speed from seed, but exceptional self-repair capability via rhizomes.
Growing Information
Origin Region
Europe and northern Asia; widely naturalized and cultivated across North America and temperate regions worldwide
Growth Habit
Aggressively rhizomatous, spreading underground to form a dense, uniform sod
Sunlight & Water Needs
Requires full sun (minimum 6 hours of direct sunlight) for optimal performance, with moderate-to-high water needs. Good dormancy mechanism during severe drought, but requires irrigation to maintain active summer growth. Prefers well-drained, fertile soils with a pH between 6.0 and 7.0.
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.5 inches. Requires regular mowing during active spring and fall growth. High maintenance level requiring 2 to 4 lbs of nitrogen per 1,000 sq ft annually, regular aeration, and occasional dethatching.
Special Characteristics
Good wear tolerance and excellent recuperative ability due to aggressive rhizomes. Moderate tolerance to shade, but susceptible to certain diseases like dollar spot, leaf spot, and summer patch under stress. Excellent winter color retention in milder cool-season zones.
Ecological Information
Introduced species in North America. Provides good soil stabilization and erosion control through dense sod formation. High wildlife value for grazing and cover. Commonly blended with perennial ryegrass and fine or tall fescues for lawns and sports turf.