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 turf-type cultivars (e.g., 'Midnight', 'Bewitched'), known for dark green color and dense sod formation
Hardiness Zones
USDA Hardiness Zones 3 to 7, thriving in northern temperate climates with cold winters and moderate summers.
About This Grass
Forms a dense, high-quality turf with medium-fine texture and a rich dark green to blue-green color. Mown height typically ranges from 2 to 3.5 inches, while unmown plants can reach 18 to 24 inches with pyramidal panicle seed heads.
Blade Characteristics
Medium width (3-4mm), folded in the bud (vernation), flat or V-shaped with distinctive parallel veins and prominent boat-shaped tips. Ligule is short and membranous; auricles are absent.
Root System
Moderately deep fibrous root system combined with aggressive rhizomes, creating a dense sod. Moderate establishment speed with a tendency to form thatch if heavily fertilized.
Growing Information
Origin Region
Native to Europe and northern Asia, widely naturalized and cultivated across North America and cool temperate regions globally
Growth Habit
Rhizomatous, spreading extensively via underground stems to form a dense, uniform turf mat
Sunlight & Water Needs
Requires full sun (minimum 6 hours of direct sunlight) for best performance, though some cultivars offer moderate shade tolerance. High watering needs to maintain green color during summer; enters drought-induced dormancy if unwatered.
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.5 inches. Requires frequent mowing during peak spring growth. High maintenance level, needing 3-4 lbs of nitrogen per 1000 sq ft annually, regular irrigation, and periodic dethatching/aeration.
Special Characteristics
Excellent wear tolerance and self-healing ability due to rhizomes. Good cold tolerance and winter color retention in milder zones, but susceptible to summer stress, drought dormancy, and certain diseases like dollar spot and leaf blight.
Ecological Information
Introduced species in North America. Provides uniform ground cover, prevents soil erosion, and filters runoff. Often blended with perennial ryegrass and fine fescues for balanced lawn durability.