Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Common lawn variety (likely a mixture including 'Midnight' or similar cultivars given the dark color)
Hardiness Zones
USDA Hardiness Zones 2-7; excellent cold tolerance; enters dormancy during extreme heat or winter freezes.
About This Grass
A dense, low-growing turf grass with a dark blue-green hue. It creates a lush carpet-like appearance when well-maintained and goes dormant/brown during summer heat or severe drought if not irrigated.
Blade Characteristics
Fine to medium width (2-4mm); V-shaped or folded vernation; distinct boat-shaped leaf tip; dark green to blue-green color; smooth leaf surface with a prominent central vein; ligule is short and membranous; auricles are absent.
Root System
Fibrous and rhizomatous; moderate depth; produces thatch over time; relatively slow establishment from seed but high recuperative potential due to underground rhizomes.
Growing Information
Origin Region
Europe, North Asia, and North Africa; now dominant throughout cool-temperate North America
Growth Habit
Rhizomatous (spreading via underground stems/rhizomes), forming a dense, self-repairing sod
Sunlight & Water Needs
Full sun preferred (6-8 hours); moderate shade tolerance; high water requirements especially in summer; prefers well-drained fertile soils with pH 6.0-7.5.
Mowing & Maintenance
Ideal height 2.5-3.5 inches; frequent mowing required during peak spring/fall growth; 2-4 lbs Nitrogen per 1000 sq ft annually; high maintenance level.
Special Characteristics
Excellent wear tolerance and recovery; susceptible to summer patch and necrotic ring spot; high aesthetic quality for home lawns and sports fields.
Ecological Information
Introduced and naturalized; provides soil stabilization via dense rhizome network; good habitat for small insects but can be invasive in native meadow ecosystems.