Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass, Pasture, and Erosion Control
Variety / Cultivar
Common-type (likely a legacy or non-turf-specific variety based on bunching and dormancy)
Hardiness Zones
USDA Zones 2-7; excellent cold tolerance, poor heat tolerance in the deep South.
About This Grass
A dark green to blue-green perennial grass that forms a thick sod. It remains low when mowed but can reach 12-36 inches if left unmowed. It produces panicle-type seed heads that are pyramid-shaped.
Blade Characteristics
Fine to medium width (2-4mm), folded in the bud (vernation), with a distinct 'boat-shaped' tip and two prominent parallel veins (trolley tracks) down the center. Ligule is short and membranous; auricles are absent.
Root System
Abundant fibrous roots and shallow-to-medium depth rhizomes (2-6 inches deep). Forms a dense thatch layer and has excellent sod-forming capabilities.
Growing Information
Origin Region
Europe, Northern Asia, and North Africa; now cosmopolitan in temperate climates
Growth Habit
Rhizomatous (spreading via underground stems), though forms dense clumps in suboptimal conditions
Sunlight & Water Needs
Prefers full sun (minimum 6 hours) but tolerates light shade. Requires moderate to high watering; will enter summer dormancy (turn brown) during severe drought to survive.
Mowing & Maintenance
Ideal height of 2.0-3.5 inches. High maintenance: requires regular fertilization (2-4 lbs N/1000 sq ft/year) and occasional dethatching/aeration.
Special Characteristics
Excellent wear tolerance and recovery due to rhizomes; susceptible to leaf spot, melting out, and necrotic ring spot during humid periods.
Ecological Information
Introduced and naturalized in North America. Provides forage for livestock and wildlife; stabilizes soil effectively through its dense rhizome network.