Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass and Pasture Grass
Variety / Cultivar
Common or Elite-type Bluegrass (e.g., 'Midnight' or 'Baron' based on dark green hue in lawn)
Hardiness Zones
USDA Zones 2-7; excellent cold tolerance but goes dormant/brown during extreme summer heat or drought.
About This Grass
A medium-textured turf grass that forms a high-density lawn. It is famous for its dark green to blue-green color. When mowed, it provides a smooth, uniform surface; unmowed, it can reach 12-24 inches with panicle-shaped seed heads.
Blade Characteristics
Fine to medium width (2-4mm), flat or slightly V-shaped, with a distinctive boat-shaped (keeled) tip. Vernation is folded in the bud. Ligule is short and membranous; auricles are absent.
Root System
Moderately shallow fibrous root system supplemented by strong rhizomes. Provides excellent sod strength and recovery from wear; tends to form thatch over time.
Growing Information
Origin Region
Native to Europe, Northern Asia, and the mountains of Morocco and Algeria; highly adapted to North American temperate climates.
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense, sod-forming mat with a medium rate of spread.
Sunlight & Water Needs
Prefers full sun (minimum 6 hours) but has moderate shade tolerance. High water requirements; requires regular irrigation during summer to prevent dormancy.
Mowing & Maintenance
Ideal height 2.0-3.5 inches. Requires 2-4 lbs of Nitrogen per 1000 sq ft annually. High maintenance level due to fertilization and dethatching needs.
Special Characteristics
Excellent traffic tolerance and recovery due to rhizomes. Susceptible to summer patch, dollar spot, and necrotic ring spot. Highly valued for aesthetic appeal.
Ecological Information
Introduced and naturalized in North America. Provides significant erosion control through dense sod. Serves as a primary forage for livestock and shelter for small fauna.