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
Variety / Cultivar
Common or Elite Cultivar (e.g., 'Midnight', 'Baron')
Hardiness Zones
USDA Zones 2-7; excellent cold tolerance but poor heat tolerance in the Deep South. Enters winter dormancy and turns straw-colored in freezing temperatures.
About This Grass
A medium-textured, deep green to blue-green grass with a dense, carpet-like growth habit. It grows 6-12 inches unmowed but is typically maintained low. It goes dormant in high heat/drought and turns brown until cooler weather or irrigation returns.
Blade Characteristics
Fine to medium width (2-4mm), V-shaped or folded vernation, distinctive boat-shaped (keeled) leaf tip, smooth texture with two prominent veins parallel to the midrib ('twin tracks'), short membranous ligule, and no auricles.
Root System
Relatively shallow fibrous root system supported by extensive rhizomes. Forms heavy thatch if over-fertilized. Slow to establish from seed (2-3 weeks) but excellent recovery from wear due to rhizome spread.
Growing Information
Origin Region
Native to Europe, North Asia, and mountains of Algeria and Morocco; widely adapted to temperate climates
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense sod or mat
Sunlight & Water Needs
Full sun preferred (6-8 hours), low to moderate shade tolerance. High water requirements; requires consistent moisture to stay green during summer months. Prefers well-drained soil with pH 6.0-7.0.
Mowing & Maintenance
Ideal height 2.0-3.5 inches. Moderate to high maintenance; requires 2-4 lbs Nitrogen per 1000 sq ft annually. Needs periodic aeration and dethatching; often mixed with fine fescue or perennial ryegrass for better performance.
Special Characteristics
Self-repairing through rhizomes, excellent wear tolerance for foot traffic, superior winter hardiness, susceptible to leaf spot and dollar spot diseases if over-watered.
Ecological Information
Introduced in North America (naturalized), provides cover for small mammals, high soil stabilization due to sod-forming habit, often used in mixtures to provide stability and color.