Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae
Grass Category
Lawn/Turf Grass, Sports Turf
Variety / Cultivar
Common blend, often varieties like 'Midnight' or 'Baron'
Hardiness Zones
USDA Hardiness Zones 3-7, excellent cold tolerance, struggles in extreme southern heat unless heavily irrigated.
About This Grass
Forms a dense, fine-to-medium textured carpet with vibrant green to blue-green color. Matures up to 18-24 inches if left unmowed but typically maintained at 1.5-2.5 inches. Prone to summer dormancy under severe heat and drought if unwatered, turning brown before greening up in fall.
Blade Characteristics
Fine to medium width (2-4mm), flat to folded with distinct parallel veins and characteristic boat-shaped tips. Vernation is folded in the bud with a short, membranous ligule and absent auricles.
Root System
Moderate to deep fibrous root system combined with extensive underground rhizomes. High thatch-forming tendency under high nitrogen and moisture. Moderate establishment speed from seed.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America in cool-temperate regions
Growth Habit
Rhizomatous, spreading underground via aggressive horizontal shoots to form a dense, uniform turf
Sunlight & Water Needs
Requires full sun (minimum 6 hours of direct sunlight), moderate to high water needs, fair drought tolerance by entering summer dormancy, prefers well-drained fertile soils with a pH of 6.0-7.0.
Mowing & Maintenance
Ideal mowing height from 2.0 to 3.0 inches. Medium to high maintenance level, requiring regular fertilization (2-4 lbs N per 1000 sq ft per year), periodic dethatching, and core aeration.
Special Characteristics
Exceptional wear tolerance and self-repairing capability via rhizomes, moderate shade tolerance, good disease resistance when properly managed, excellent cold-weather color retention compared to warm-season grasses.
Ecological Information
Introduced species in North America, provides standard wildlife cover and soil erosion control, commonly blended with Perennial Ryegrass and Fine Fescues for home lawns and sports fields.