Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 carbon fixation pathway
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf, and Golf Course Grass
Variety / Cultivar
Common or 'Midnight' type based on dark hue; exhibiting typical high-density turf characteristics
Hardiness Zones
USDA Hardiness Zones 3-7. Excellent cold tolerance; poor heat tolerance in southern climates where it goes dormant without irrigation.
About This Grass
A smooth, upright perennial grass that forms a high-quality, dense turf. It is a rich, medium-to-dark green color and enters dormancy during extreme heat or cold. Unmowed, it reaches 12-24 inches with an open, pyramidal panicle seed head.
Blade Characteristics
Blade width is fine to medium (2-4mm). Features a distinct boat-shaped (V-shaped) tip and a smooth surface with a prominent center vein. Vernation is folded in the bud; ligule is short and membranous; auricles are absent.
Root System
Fibrous and rhizomatous system; roots are moderately shallow compared to fescues. High thatch-forming tendency due to rhizome production. Slow establishment from seed (2-3 weeks) but forms a very durable sod.
Growing Information
Origin Region
Native to Europe, North Asia, and the mountains of Morocco and Algeria; widely adapted to temperate regions worldwide
Growth Habit
Rhizomatous (spreading underground via rhizomes), forming a dense, tight-knit sod with a medium rate of spread
Sunlight & Water Needs
Prefers Full Sun (minimum 6 hours); moderate shade tolerance. High water requirement, needing 1-1.5 inches per week. Prefers well-drained, fertile soils with a pH between 6.0 and 7.5.
Mowing & Maintenance
Ideal height is 2.0-3.5 inches. High maintenance level; requires 3-5 lbs of Nitrogen per 1000 sq ft annually and regular dethatching/aeration to manage the rhizome mat.
Special Characteristics
Excellent wear tolerance and recovery due to self-repairing rhizomes. Susceptible to leaf spot, melting out, and necrotic ring spot. High aesthetic value for residential and professional landscapes.
Ecological Information
Introduced and naturalized in North America. Provides soil stabilization and filtration; can be aggressive in native meadows. Often blended with Perennial Ryegrass or Fine Fescue for improved resilience.