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
Standard general-purpose lawn cultivars (e.g., 'Midnight', 'Baron')
Hardiness Zones
Thrives in USDA Hardiness Zones 3-7, with good cold tolerance down to -30°F or lower. Performs best in northern regions and the upper transition zone.
About This Grass
Forms a very dense, fine-to-medium textured turf with a rich blue-green to dark green color. Reaches up to 18-24 inches if unmowed, but maintained at 1.5-2.5 inches. Produces open, pyramidal panicle seed heads at maturity.
Blade Characteristics
Blades are medium-fine (2-4mm wide), flat to folded with distinct parallel veins and characteristic boat-shaped (prow-shaped) tips. Vernation is folded in the bud. Ligule is short and membranous, auricles are absent.
Root System
Moderately deep fibrous root system combined with extensive underground rhizomes. Establishes slowly from seed, has moderate thatch tendency, and forms an extremely tough, resilient sod.
Growing Information
Origin Region
Europe, northern Asia, and parts of the mountains of western North America; widely cultivated in cool, humid, and transitional regions worldwide.
Growth Habit
Rhizomatous with aggressive underground spreading, forming a dense, uniform sod.
Sunlight & Water Needs
Requires full sun (at least 6-8 hours of direct sunlight) and moderate to high moisture levels. Moderate drought tolerance (enters dormancy during severe drought) and prefers well-drained, fertile soils with a pH of 6.0-7.0.
Mowing & Maintenance
Ideal mowing height is 1.5 to 2.5 inches. Requires frequent mowing during peak spring/fall growth. High maintenance level needing regular fertilization (3-4 lbs N per 1000 sq ft annually), periodic aeration, and dethatching.
Special Characteristics
Exceptional wear tolerance and self-repairing capability due to rhizomes. Good cold hardiness and winter color retention, but moderate heat tolerance and susceptible to summer dormancy without irrigation.
Ecological Information
Introduced species in North America. Provides good soil stabilization and erosion control due to dense root and rhizome network. Often blended with Perennial Ryegrass and Fine Fescue for resilient lawn mixes.