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
General turf type (e.g., 'Midnight' or 'Baronie'), exhibiting dark green color and dense sod formation.
Hardiness Zones
Thrives in USDA Hardiness Zones 3 through 7. Excellent cold tolerance, but struggles with extreme summer heat unless irrigated, making it less ideal for the deep southern transition zone.
About This Grass
Forms a dense, plush turf with a medium texture and rich dark green to blue-green color. Mown turf height is typically maintained between 2 to 3 inches, while unmowed grass can grow up to 18-24 inches with open, pyramidal panicle seed heads.
Blade Characteristics
Blades are medium width (2-4 mm), 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 complemented by an aggressive network of underground rhizomes. Tends to build thatch over time if heavily fertilized. Moderate to slow establishment speed from seed.
Growing Information
Origin Region
Native to Europe, northern Asia, and parts of the mountains of North America. Widely cultivated throughout cool-temperate regions worldwide.
Growth Habit
Rhizomatous, spreading extensively via underground creeping stems to form a dense, uniform turf and resilient sod.
Sunlight & Water Needs
Requires full sun (minimum 6 hours of direct sunlight) for optimal growth, though some cultivars offer moderate shade tolerance. High watering needs to maintain green color during dry periods; goes dormant under severe drought.
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.5 inches. Requires regular mowing, moderate to high fertilization (2-4 lbs N per 1000 sq ft annually), periodic dethatching, and core aeration. Maintenance level is considered Medium to High.
Special Characteristics
Exceptional wear tolerance and self-healing capability via rhizomes. Good cold and drought recovery through dormancy. Prone to certain fungal diseases like dollar spot, leaf spot, and summer patch under high humidity and stress.
Ecological Information
Widely naturalized in North America. Provides good soil stabilization and erosion control due to dense root and rhizome matrix. Frequently blended with Perennial Ryegrass and Tall Fescue in commercial seed mixes.