Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf, Golf Course Grass
Variety / Cultivar
Common or various turf-type cultivars (e.g., 'Midnight', 'Compact Midnight')
Hardiness Zones
USDA Hardiness Zones 3 to 7, exhibits excellent cold tolerance but can struggle with extreme summer heat in southern transition zones unless irrigated.
About This Grass
Forms a dense, high-quality turf with a medium-fine texture and rich blue-green color. Reaches 18 to 24 inches if unmowed, but maintained at 1.5 to 2.5 inches. Produces open, pyramidal panicle seed heads at maturity.
Blade Characteristics
Blades are medium-fine (2-3 mm wide), flat or folded with distinct parallel veins and prominent boat-shaped tips. Vernation is folded in the bud. Ligule is short and membranous, with no auricles.
Root System
Moderate to deep fibrous root system combined with extensive underground rhizomes. Moderate establishment speed, forms a dense sod, and has a tendency to develop thatch under high maintenance.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America and temperate regions worldwide
Growth Habit
Aggressively rhizomatous, forming a dense, uniform turf sod
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily) for best performance, though some cultivars show moderate shade tolerance. High water needs during dry spells; goes into summer dormancy if unwatered. Prefers fertile, well-drained soils with a pH of 6.0 to 7.0.
Mowing & Maintenance
Ideal mowing height is 1.5 to 3.0 inches. Medium to high maintenance level, requiring regular fertilization (2-4 lbs N per 1000 sq ft annually), frequent mowing, and periodic dethatching and core aeration.
Special Characteristics
Exceptional wear tolerance and self-repairing capability via rhizomes. Good cold hardiness and winter color retention in milder cool-season climates. Moderate disease susceptibility to leaf spot, dollar spot, and summer patch.
Ecological Information
Introduced species in North America. Provides dense soil stabilization and erosion control. Commonly blended with perennial ryegrass and fine fescues for home lawns and sports fields.