Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
AI-generated identification · may be incorrect
Grass Category
Lawn/Turf Grass, Sports Turf, Erosion Control
Hardiness Zones
Thrives in USDA Hardiness Zones 3 through 7. Excellent cold tolerance, but struggles with extreme summer heat and humidity in the deep southern transition zones unless irrigated.
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Variety / Cultivar
Standard common and improved turf types (e.g., 'Midnight', 'Bewitched')
About This Grass
Forms a dense, fine to medium-textured turf with an attractive dark green to blue-green color. It grows 1.5 to 2.5 feet tall if left unmowed, but is typically maintained at 1.5 to 2.5 inches. Exhibits winter dormancy where it turns brown or straw-colored in severe cold, but revives quickly in spring.
Blade Characteristics
Blades are medium-narrow (2-4mm wide), flat to folded with prominent parallel veins and distinctive boat-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 aggressive rhizomes, creating a dense, tough sod. Establishes relatively slowly from seed, but recovers well from damage via rhizome spread. Can develop moderate thatch if over-fertilized.
Growing Information
Origin Region
Europe and Northern Asia, widely naturalized and cultivated across North America and temperate regions worldwide
Growth Habit
Rhizomatous, spreading extensively via underground stems to form a dense, uniform turf mat
Sunlight & Water Needs
Requires full sun (at least 6-8 hours daily) for optimal growth, though some newer cultivars show moderate shade tolerance. High water requirements to maintain active growth during summer; goes into summer dormancy (browns out) under prolonged drought, recovering when moisture returns.
Mowing & Maintenance
Ideal mowing height is 1.5 to 2.5 inches. Requires regular mowing during active spring and fall growth periods. High fertilizer requirement (3-5 lbs N per 1000 sq ft annually) for optimal color and density. Medium-high maintenance level involving periodic dethatching and aeration.
Special Characteristics
Exceptional wear and traffic tolerance due to aggressive rhizomatous recovery. Good cold hardiness and winter color retention compared to warm-season grasses. Susceptible to diseases like summer patch, dollar spot, and leaf spot under high humidity and stress.
Ecological Information
Introduced to North America by European settlers. Provides moderate wildlife habitat and excellent soil stabilization/erosion control on slopes due to its dense sod-forming root and rhizome network. Frequently blended with Perennial Ryegrass and Fine Fescues for northern lawns.