Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf, Golf Course Grass
Variety / Cultivar
General/Unknown (displays characteristics typical of high-quality turf cultivars like 'Midnight' or 'Baron')
Hardiness Zones
USDA Hardiness Zones 2-7; excellent cold tolerance; poor heat tolerance; goes dormant and turns brown during extreme summer heat or winter freezes.
About This Grass
A dense, low-growing turf with a rich dark green to blue-green color. It exhibits a uniform texture and remains soft to the touch. When unmowed, it reaches 12-24 inches with open, airy panicle seed heads, but is typically maintained at a low carpet-like height.
Blade Characteristics
Fine to medium width (2-4mm); V-shaped or flat; distinctive boat-shaped (keeled) tip; dark green; folded vernation; membranous ligule (short); auricles absent; prominent midrib running down the center.
Root System
Relatively shallow fibrous root system compared to fescues, but supported by extensive rhizomes. Forms a heavy thatch layer; slow to moderate establishment speed but excellent sod strength.
Growing Information
Origin Region
Native to Europe, North Asia, and the mountains of Morocco and Algeria; best adapted to cool, humid climates
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense, sod-forming mat with a moderate rate of spread
Sunlight & Water Needs
Full sun preferred (minimum 6 hours); moderate shade tolerance; high water requirements especially in summer heat; poor drought tolerance (enters dormancy quickly during water stress); prefers well-drained fertile soil with pH 6.0-7.5.
Mowing & Maintenance
Ideal height 2.0-3.5 inches; high maintenance level; requires frequent mowing and regular fertilization (3-5 lbs Nitrogen per 1000 sq ft annually); requires periodic dethatching and core aeration.
Special Characteristics
Excellent traffic and wear tolerance due to self-repairing rhizomes; good disease resistance in modern cultivars but susceptible to necrotic ring spot and summer patch; high aesthetic value for home lawns.
Ecological Information
Introduced/Naturalized in North America; provides moderate nesting cover for small birds when left tall; excellent for soil stabilization and erosion control due to dense rhizome network; often blended with Perennial Ryegrass or Fine Fescue for improved resilience.