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 (Fairways/Tees)
Variety / Cultivar
Common or Midnight-type (exhibiting typical dense, dark-green characteristic)
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 turfgrass with a high aesthetic value. It displays a rich emerald to dark-green color. Mowed heights range from 2.5 to 3.5 inches. In unmowed states, it reaches 12-24 inches with open, airy pyramidal panicle seed heads.
Blade Characteristics
Fine to medium width (2-4mm); V-shaped or flat; boat-shaped (keeled) leaf tips; dark green to blue-green color; vernation is folded in the bud; ligule is short, membranous, and truncate; auricles are absent; prominent midvein with two translucent lines (tracks).
Root System
Moderately shallow fibrous root system with extensive horizontal underground rhizomes. High thatch tendency due to rhizome production. Slow establishment from seed (21-28 days) but forms a very durable sod.
Growing Information
Origin Region
Native to Europe, Asia, and North Africa; naturalized across North America, performing best in humid, cool temperate climates.
Growth Habit
Rhizomatous (spreading underground via rhizomes), forming a dense, sod-forming mat with a medium-fast rate of spread once established.
Sunlight & Water Needs
Full Sun (preferred), 6-8+ hours; moderate to high water needs (1 inch per week); moderate drought tolerance (enters dormancy during heat); prefers well-drained fertile soil with pH 6.0-7.2.
Mowing & Maintenance
Ideal height 2.5-3.5 inches; frequent mowing required during peak spring/fall; 3-5 lbs N per 1000 sq ft per year; high maintenance level requiring periodic dethatching and aeration.
Special Characteristics
Excellent wear tolerance and recovery due to rhizomes; susceptible to leaf spot, melting out, and necrotic ring spot; high salt sensitivity; moderate shade tolerance (varies by cultivar).
Ecological Information
Introduced species; provides high-quality cover for small mammals and food for various lepidoptera larvae; excellent soil stabilization; commonly used in seed blends with Perennial Ryegrass and Fine Fescue.