Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae
Grass Category
Lawn/Turf Grass, Sports Turf, Golf Course Grass
Variety / Cultivar
Standard general turf cultivar ('Midnight' type characteristics visible in density and color)
Hardiness Zones
USDA Hardiness Zones 3-7. Excellent cold tolerance, goes semi-dormant or brown in extreme summer heat unless irrigated. Common in northern and transition zones.
About This Grass
Forms a dense, high-quality turf with a rich medium-to-dark green color. Height ranges from 1.5 to 2.5 inches when maintained, and up to 18-24 inches if left unmowed. Texture is fine to medium with excellent density and a smooth appearance.
Blade Characteristics
Blade width is medium (approx 2-4 mm), flat to V-shaped with characteristic boat-shaped tips. Vernation is folded in the bud. Color is vibrant medium-to-dark green with prominent parallel veins. Ligule is short and membranous, auricles absent.
Root System
Moderate depth fibrous root system with extensive aggressive rhizomes. Forms a very tough, dense sod. Moderate to slow establishment speed from seed, and a moderate tendency to form thatch under high fertilization.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America and temperate regions worldwide.
Growth Habit
Rhizomatous, spreading extensively via underground stems to form a dense, uniform turf mat.
Sunlight & Water Needs
Performs best in full sun (minimum 6-8 hours daily), moderate to high water requirements to maintain green color during summer, moderate drought tolerance (enters summer dormancy during severe dry spells). Prefers well-drained, fertile soils with a pH of 6.0-7.0.
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.0 inches. Mowing frequency is weekly during active spring and fall growth. Requires moderate to high maintenance, including 3-5 lbs N per 1000 sq ft annually, regular irrigation, and occasional dethatching.
Special Characteristics
High wear tolerance due to aggressive rhizomes and excellent self-repairing capability. Good disease resistance when properly managed, though susceptible to summer patch, dollar spot, and rust under stress. Poor shade tolerance compared to fescues.
Ecological Information
Introduced species in North America. Provides good soil stabilization and erosion control due to dense sod formation. Frequently blended with perennial ryegrass and fine fescues for home lawns and sports fields.