Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae
Grass Category
Lawn/Turf Grass, Sports Turf
Variety / Cultivar
Common blend (such as 'Midnight' or 'Baron')
Hardiness Zones
USDA Hardiness Zones 3 to 7, exhibits excellent cold tolerance, moderate heat tolerance, and goes dormant during severe summer heat or drought.
About This Grass
Forms a dense, fine-to-medium textured, rich green to blue-green turf. Height can reach 18 to 24 inches if unmowed, but maintained lawns are typically kept at 1.5 to 2.5 inches. Features open, pyramidal panicle seed heads at maturity.
Blade Characteristics
Medium-fine width (2-4mm), flat to folded shape with characteristic boat-shaped tips and prominent parallel veins. Vernation is folded in the bud. Ligule is short and membranous; auricles are absent.
Root System
Moderately deep fibrous root system combined with extensive underground rhizomes. Can develop a moderate thatch layer if over-fertilized. Establishes slowly from seed, but forms an extremely tough, dense sod once mature.
Growing Information
Origin Region
Europe, Northern Asia, and mountainous regions of North America; widely cultivated throughout cool temperate regions worldwide
Growth Habit
Aggressively rhizomatous, spreading via underground stems to form a dense, uniform turf mat
Sunlight & Water Needs
Requires full sun (at least 6-8 hours daily) for optimal growth, with moderate to high water needs. Has fair drought tolerance by entering summer dormancy during extended dry spells, preferring well-drained loamy soils with a pH of 6.0-7.0.
Mowing & Maintenance
Maintain at a mowing height of 2.0 to 3.0 inches. Requires a medium-to-high maintenance level, needing regular fertilization (3-4 lbs N per 1000 sq ft per year), periodic dethatching, and regular irrigation during dry periods.
Special Characteristics
Excellent self-repairing capabilities due to rhizomes, good traffic tolerance once established, moderate disease susceptibility (e.g., leaf spot, dollar spot, summer patch), and superior winter color retention compared to warm-season grasses.
Ecological Information
Introduced species in North America, widely used in lawn mixes with perennial ryegrass and fescues. Provides standard turf ecosystem benefits including erosion control, oxygen production, and cooling, but limited native wildlife forage value.