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 Fairway/Rough
Variety / Cultivar
Common or Elite types (e.g., Midnight, Baron, or Boutique based on dark green color and density)
Hardiness Zones
USDA Hardiness Zones 2-7; excellent cold tolerance; poor heat tolerance in the Deep South; enters winter dormancy turning brown/tan in sub-freezing temps.
About This Grass
A dense, low-growing turf grass with a distinct deep green to blue-green color. It forms a lush, uniform carpet that goes dormant in extreme heat. Seed heads are open, spreading panicles (pyramidal shape) when unmowed.
Blade Characteristics
Fine to medium width (2-4mm); V-shaped or flat; distinctive boat-shaped (keeled) tip; smooth texture with a prominent midrib; folded vernation; ligule is short and membranous; auricles are absent.
Root System
Relatively shallow fibrous root system augmented by extensive rhizomes. High thatch tendency due to organic matter accumulation; medium establishment speed from seed (21+ days).
Growing Information
Origin Region
Native to Europe, North Asia, and Morocco; widely adapted across Northern US and Canada
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense, self-repairing sod
Sunlight & Water Needs
Full sun preferred (6-8 hours); moderate to high water needs; goes dormant during drought as a survival mechanism; prefers well-drained soil with pH 6.0-7.5.
Mowing & Maintenance
Ideal height 2.0-3.5 inches; high maintenance; requires 2-4 lbs Nitrogen per 1000 sq ft annually; needs periodic dethatching and aeration to manage rhizome mat.
Special Characteristics
Excellent traffic/wear tolerance due to rhizomes; superior recuperative potential; high aesthetic quality; susceptible to leaf spot, melting out, and necrotic ring spot.
Ecological Information
Introduced/Naturalized (non-native to NA); provides nesting cover for ground-dwelling birds; high soil stabilization on slopes; often blended with Perennial Ryegrass or Fine Fescue for genetic diversity.