Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Common or Elite-type Kentucky Bluegrass (unspecified cultivar)
Hardiness Zones
USDA Hardiness Zones 2-7; excellent cold tolerance; poor heat tolerance (goes dormant in high heat); successful in the Transition Zone with irrigation.
About This Grass
A dense, low-growing turf with a rich green to blue-green color. It features smooth, upright-growing blades that form a lush carpet. When unmowed, it reaches 12-24 inches with open, pyramidal panicle seed heads.
Blade Characteristics
Fine to medium width (2-4mm); V-shaped or flat; distinctive boat-shaped (keeled) tip; dark green to blue-green; folded vernation; membranous ligule (very short); auricles absent.
Root System
Moderately deep fibrous root system combined with strong rhizomes; high thatch-forming tendency; moderate establishment speed from seed; excellent sod-forming ability.
Growing Information
Origin Region
Native to Europe, North Asia, and mountains of Algeria and Morocco; highly adapted to temperate climates
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense, self-repairing sod
Sunlight & Water Needs
Full sun preferred (requires 6+ hours); moderate shade tolerance; high water needs (1 inch per week); enters summer dormancy during extreme drought but has high recovery capacity.
Mowing & Maintenance
Ideal height 2.5 to 3.5 inches; weekly mowing; requires 2-4 lbs N per 1,000 sq ft annually; high maintenance; necessitates periodic aeration and dethatching.
Special Characteristics
Excellent wear tolerance and recovery due to rhizomes; susceptible to leaf spot, melting out, and necrotic ring spot; moderate salt tolerance; iconic 'boat-shaped' tip helps distinguish it from fescues.
Ecological Information
Introduced and naturalized in North America; provides cover for small mammals and food for various lepidoptera larvae; excellent soil stabilizer for erosion control on slopes.