Kentucky Bluegrass
Poa pratensis · Cool-season, perennial, C3 grass
AI-generated identification · may be incorrect
Grass Category
Lawn/Turf Grass, Sports Turf, Golf Course Grass
Hardiness Zones
USDA Hardiness Zones 3 to 7 (thrives in northern climates, struggles in extreme southern heat). Excellent cold tolerance. Can survive in the transition zone with adequate irrigation and management.
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Variety / Cultivar
Midnight type (dark green, dense, highly rated for color and disease resistance)
About This Grass
Forms a dense, high-quality, fine-to-medium textured turf with rich dark green to blue-green color. Height ranges from 1.5 to 3 inches when maintained as a lawn, but can reach 18 to 24 inches if left unmowed. Produces open, pyramid-shaped panicle seed heads at maturity.
Blade Characteristics
Medium width (3-4mm), flat to folded shape with distinctive boat-shaped tips. Color ranges from medium to dark green or blue-green. Vernation is folded in the bud. Ligule is short and membranous. Auricles are absent. Collar is narrow and continuous.
Root System
Moderately deep fibrous root system (6 to 18 inches) combined with vigorous rhizomes. High tendency to form thatch if over-fertilized. Moderate establishment speed (can take 21-30 days to germinate from seed), but recovers well from stress due to rhizomatous spreading.
Growing Information
Origin Region
Native to Europe, northern Asia, and parts of the mountains of North America; widely cultivated throughout the northern United States and Canada
Growth Habit
Aggressively rhizomatous, forming a dense, uniform turf and strong sod via underground stems
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily), has poor to moderate shade tolerance. High watering needs to maintain active growth during dry summer months; goes into summer dormancy (turning brown) during severe drought. Prefers well-drained fertile soils with a pH of 6.0 to 7.0.
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.0 inches. Requires frequent mowing during peak spring and fall growth periods. High fertilization needs (3-5 lbs N per 1000 sq ft per year). Regular dethatching and annual core aeration are beneficial due to heavy thatch and sod formation. High maintenance level.
Special Characteristics
Exceptional wear tolerance and traffic recovery due to spreading rhizomes. Moderate shade tolerance compared to fine fescues. Susceptible to certain diseases like dollar spot, summer patch, and leaf spot under high humidity and improper fertilization. Excellent erosion control.
Ecological Information
Introduced species in North America widely naturalized in cool temperate regions. Provides standard lawn ecosystem services including soil stabilization, carbon sequestration, and cooling effects. Often blended with Perennial Ryegrass and Tall Fescue in seed mixes.