Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 physiological pathway
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf, Golf Course Fairways/Tees
Variety / Cultivar
Likely a common turf-type variety (e.g., Midnight, Baron, or Blue Note), though field-level identification requires genetic testing.
Hardiness Zones
USDA Hardiness Zones 2-7; excellent cold tolerance; poor heat tolerance in deep South; goes dormant/brown in winter in cold climates.
About This Grass
A dark-to-medium green grass that forms a plush, thick mat. When unmowed, it reaches 12-24 inches with a pyramidal panicle seed head; maintained at turf height, it is dense and soft-textured.
Blade Characteristics
Fine to medium width (2-4mm); V-shaped or flat; distinctive 'boat-shaped' (keeled) tip; folded vernation; short membranous ligule; auricles absent; smooth collar.
Root System
Moderately shallow fibrous roots with aggressive rhizomes; forms heavy thatch; medium establishment speed; rhizomes provide excellent recovery from wear.
Growing Information
Origin Region
Native to Europe, North Asia, and mountains of Algeria/Morocco; Widely naturalized in temperate North America.
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense, self-repairing sod.
Sunlight & Water Needs
Full Sun preferred (6+ hours); moderate shade tolerance; high water requirements (1-1.5 inches per week); enters summer dormancy during severe drought.
Mowing & Maintenance
Ideal height 2.0-3.5 inches; frequent mowing required; high nitrogen needs (3-5 lbs N/1000 sq ft/yr); high maintenance level including aeration and dethatching.
Special Characteristics
Excellent traffic tolerance and recovery; susceptible to necrotic ring spot and summer patch; high salt sensitivity; moderate shade tolerance (varies by cultivar).
Ecological Information
Introduced species in North America; provides soil stabilization via dense sod; high water filtration value; can be invasive in native meadows/prairies; often blended with Perennial Ryegrass or Fine Fescue.