Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
AI-generated identification · may be incorrect
Grass Category
Lawn/Turf Grass
Hardiness Zones
USDA Hardiness Zones 3 to 7, exhibits excellent cold tolerance, moderate heat tolerance, goes dormant in extreme heat or drought, and acts as a primary cool-season turf in northern regions and parts of the upper transition zone.
Grass Family
Poaceae, subfamily Pooideae
Variety / Cultivar
Midnight (known for dark blue-green color and dense growth)
About This Grass
Forms a dense, fine-to-medium textured sod with rich dark green to blue-green color. Mowed height ranges from 1.5 to 2.5 inches; unmowed height can reach 18 to 24 inches with distinctive pyramidal panicle seed heads.
Blade Characteristics
Fine-to-medium width (2-4mm), flat to folded shape with characteristic boat-shaped tips. Dark blue-green color, folded vernation in the bud, prominent parallel veins with a tram-line effect. Membranous ligule, absent auricles, and a narrow collar region.
Root System
Moderate to deep fibrous root system with extensive underground rhizomes. Moderate thatch-forming tendency under high fertility and watering. Slow to moderate establishment speed from seed, but forms extremely dense, wear-recovering sod once mature.
Growing Information
Origin Region
Europe, northern Asia, and the mountains of North America; widely cultivated throughout cool and transition zones globally
Growth Habit
Rhizomatous, spreading underground via aggressive creeping rhizomes to form a dense, uniform turf mat
Sunlight & Water Needs
Requires full sun (minimum 6 hours of direct sunlight), though some modern cultivars have moderate shade tolerance. High watering needs to maintain green color during summer; goes into summer dormancy under drought conditions. Prefers well-drained, fertile soils with a pH of 6.0 to 7.0.
Mowing & Maintenance
Ideal mowing height between 2.0 and 3.0 inches. Mowing frequency is high during spring and fall peak growth. High fertilizer requirement (3 to 4 lbs N per 1000 sq ft per year). Requires regular dethatching and aeration due to dense rhizome and thatch buildup. High overall maintenance level.
Special Characteristics
Good traffic and wear tolerance due to aggressive rhizomatous recovery, moderate disease susceptibility (susceptible to leaf spot, dollar spot, and summer patch), good drought recovery via underground rhizomes, poor shade tolerance compared to fescues, excellent erosion control.
Ecological Information
Introduced species in North America, provides standard turf ecosystem benefits including soil stabilization, carbon sequestration, and urban heat island reduction. Often blended with perennial ryegrass and fine fescues for balanced lawn establishment.