Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae
Grass Category
Lawn/Turf Grass and Sports Turf
Variety / Cultivar
Standard turf-type cultivars (e.g., 'Midnight', 'Baron')
Hardiness Zones
Thrives in USDA Hardiness Zones 3 to 7, tolerating cold winters well but struggling with extreme summer heat and humidity in the deep south unless irrigated.
About This Grass
Forms a dense, fine-to-medium textured turf with rich dark green to blue-green coloration. Height ranges from 1.5 to 2.5 inches when maintained, but can reach 18-24 inches if left unmowed, producing open, pyramidal panicle seed heads.
Blade Characteristics
Blades are medium-narrow (2-4mm wide), flat to folded with distinct parallel veins and characteristic boat-shaped tips. Vernation is folded in the bud. Ligule is short and membranous; auricles are absent.
Root System
Moderately deep fibrous root system combined with aggressive underground rhizomes. Tends to form a moderate thatch layer over time. Establishes slowly from seed but recovers well from damage due to spreading rhizomes.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America and temperate regions worldwide
Growth Habit
Rhizomatous, spreading underground via robust rhizomes to form a dense, uniform sod
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily) for optimal growth, with moderate to high water needs. Has moderate drought tolerance, entering summer dormancy during extended dry periods, and prefers well-drained fertile soils with a pH of 6.0 to 7.0.
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.0 inches. Requires frequent mowing during peak spring/fall growth seasons. Fertilization needs are moderate to high (3-4 lbs N per 1000 sq ft annually). Requires periodic dethatching and aeration. Overall maintenance level is medium to high.
Special Characteristics
Excellent wear tolerance and traffic recovery due to rhizomatous growth habit. Moderate to good cold and frost tolerance. Fairly susceptible to certain diseases like dollar spot and summer patch under stress, but forms an exceptional self-repairing home lawn or sports turf.
Ecological Information
Introduced species in North America. Provides good soil stabilization and erosion control due to dense root and rhizome matrix. Often blended with perennial ryegrass and fine fescues in turf seed mixes.