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
Common blend or traditional cultivars like 'Midnight' or 'Baron'
Hardiness Zones
USDA Hardiness Zones 3-7, with good cold tolerance down to -30F or lower, but struggles with extreme summer heat unless irrigated.
About This Grass
Forms a dense, fine to medium-textured turf with a rich dark green to blue-green color. Matures up to 18-24 inches if unmowed, but usually maintained at 2-3 inches. Features prominent boat-shaped leaf tips and pyramid-shaped panicle seed heads.
Blade Characteristics
Medium width (2-4mm), flat to folded in the bud with distinctive boat-shaped tips and parallel veins. Membranous ligule, absent auricles, and a continuous whitish midrib visible on the underside.
Root System
Moderately deep fibrous root system combined with aggressive rhizomes, creating a dense, heavy sod. Moderate establishment speed, moderate thatch-forming tendency under high fertility.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America, performing best in northern regions and the cooler transition zones
Growth Habit
Rhizomatous, spreading extensively via underground stems to form a dense, uniform turf and tough sod
Sunlight & Water Needs
Requires full sun (minimum 6 hours daily) for best performance, with moderate to high water needs. Enters summer dormancy during severe drought but recovers well when moisture returns. Prefers well-drained, fertile loams with pH 6.0-7.0.
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.5 inches. High maintenance level requiring regular fertilization (3-4 lbs N per 1000 sq ft per year), periodic dethatching, and reliable irrigation during dry spells.
Special Characteristics
Excellent wear tolerance and self-healing ability due to rhizomes. Good cold tolerance and winter dormancy color retention depending on the cultivar. Fair shade tolerance compared to fine 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 Tall Fescue in northern turf mixes.