Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3
Grass Family
Poaceae, subfamily Pooideae
Grass Category
Lawn/Turf Grass, Sports Turf
Variety / Cultivar
Common blend/cultivars (e.g., 'Midnight', 'Bewitched')
Hardiness Zones
USDA Hardiness Zones 3 to 7, excellent cold tolerance, struggles in extreme summer heat unless irrigated, moderately successful in northern transition zones.
About This Grass
Forms a dense, high-quality turf with a medium-fine texture and rich dark green to blue-green color. Reaches up to 18-24 inches if unmowed, but maintained at 1.5 to 2.5 inches. Features pyramid-shaped panicle seed heads at maturity.
Blade Characteristics
Medium-fine width (2-4mm), flat to folded shape with distinctive boat-shaped tips and parallel sides. Vernation is folded in the bud. Features prominent parallel veins giving a railroad-track appearance. Membranous ligule and absent auricles.
Root System
Moderately deep fibrous root system with extensive rhizomes, forming a very strong, dense sod. Moderate establishment speed from seed, tends to build up thatch over time.
Growing Information
Origin Region
Europe and Northern Asia; widely cultivated across North America, especially northern and transition zones
Growth Habit
Rhizomatous, spreading underground via aggressive underground stems to form a dense, uniform turf
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily) for best performance, though some cultivars have moderate shade tolerance. High watering needs during dry spells to maintain green color, enters summer dormancy during severe drought.
Mowing & Maintenance
Ideal mowing height is 1.5 to 2.5 inches. Requires regular mowing, moderate to high fertilization (3-5 lbs N per 1000 sq ft annually), occasional dethatching and core aeration. Medium-high maintenance level.
Special Characteristics
Excellent traffic and wear tolerance due to aggressive rhizomatous recovery, good cold hardiness, moderate disease susceptibility (e.g., dollar spot, leaf spot), poor shade tolerance compared to fescues, slow to germinate from seed.
Ecological Information
Introduced species in North America, widely naturalized. Provides good soil stabilization and erosion control due to dense sod formation. Commonly blended with perennial ryegrass and fine fescues in turf seed mixes.