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 (indicated by thick emerald blades; specific variety like 'Midnight' or 'Baron' typical for home lawns)
Hardiness Zones
USDA Zones 2-7; excellent cold tolerance; poor heat tolerance in the Deep South; transitions to dormancy in summer stress.
About This Grass
A dense, low-growing turf with a rich emerald to dark green color. It exhibits a uniform texture and becomes dormant in high heat or extreme cold. Unmowed, it can reach 12-24 inches with open, pyramidal panicle seed heads.
Blade Characteristics
Fine to medium width (2-4mm); smooth, V-shaped or flat blades with a distinct 'boat-shaped' tip; folded vernation; ligule is short and membranous; auricles are absent.
Root System
Relatively shallow but dense fibrous system supplemented by spreading rhizomes; creates thick thatch and high sod strength; moderate establishment speed.
Growing Information
Origin Region
Native to Europe, Northern Asia, and the mountains of Morocco and Algeria; highly adapted to temperate climates
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense, self-repairing sod mat
Sunlight & Water Needs
Full sun preferred (6+ hours); moderate to high water needs; poor shade tolerance; enters dormancy during drought; prefers pH 6.0-7.5.
Mowing & Maintenance
1.5 to 3.0 inches height; frequent mowing required; high nitrogen needs (2-4 lbs N per 1000 sq ft/year); requires periodic aeration and dethatching.
Special Characteristics
Excellent wear tolerance and recovery due to rhizomes; high aesthetic quality; susceptible to leaf spot, melting out, and necrotic ring spot.
Ecological Information
Introduced and naturalized in North America; provides forage for livestock and nesting cover for birds; can be invasive in native grasslands; frequently blended with Perennial Ryegrass or Fine Fescue.