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 mixed turf cultivars (e.g., 'Midnight', 'Baron')
Hardiness Zones
USDA Hardiness Zones 3 to 7. Excellent cold tolerance, goes dormant in freezing winters, suffers in extreme prolonged summer heat unless irrigated.
About This Grass
Forms a dense, high-quality turf with a rich medium-to-dark green or blue-green color. Leaf blades are medium-fine in texture. When unmowed, it can reach heights of 18 to 24 inches, but it is typically maintained at 1.5 to 2.5 inches. Produces open, pyramidal panicle seed heads at maturity.
Blade Characteristics
Medium width (2-4mm), flat to folded with prominent parallel veins and a distinctive boat-shaped (prow-like) tip. Vernation is folded in the bud. Ligule is short and membranous. Auricles are absent.
Root System
Moderately deep fibrous root system combined with vigorous spreading rhizomes. Forms a very dense sod. Prone to thatch buildup if over-fertilized. Moderate establishment speed, excellent wear recovery due to rhizomes.
Growing Information
Origin Region
Europe, Northern Asia, and parts of the mountains of North America; widely cultivated throughout the northern United States, Canada, and cool temperate regions globally.
Growth Habit
Rhizomatous, forming a dense, uniform sod via underground spreading stems; moderate to slow establishment rate from seed.
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours of direct sunlight), though some modern cultivars have moderate shade tolerance. High water requirements to maintain active growth during summer; enters summer dormancy during extended drought.
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.0 inches. Medium to high maintenance level. Requires regular fertilization (2-4 lbs N per 1,000 sq ft annually), periodic aeration, and dethatching due to dense rhizome and root accumulation.
Special Characteristics
Exceptional wear tolerance and self-repairing capabilities due to rhizomatous growth. Good winter color retention in milder cool regions. Moderate salt tolerance. Susceptible to certain diseases like dollar spot, leaf spot, and summer patch.
Ecological Information
Introduced species in North America, naturalized widely. Provides good soil stabilization and erosion control due to dense root and rhizome matrix. Frequently blended with Perennial Ryegrass and Fine Fescues to create resilient turf seed mixes.