Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf
Variety / Cultivar
Common blend (such as 'Midnight' or 'Baron' type characteristics)
Hardiness Zones
Thrives in USDA Hardiness Zones 3 to 7. Excellent cold tolerance, but struggles with extreme summer heat and humidity in the deep south unless heavily irrigated.
About This Grass
Forms a lush, highly dense, medium-fine textured turf with a rich medium-to-dark green color. Unmowed height reaches 18 to 24 inches, typically maintained at 1.5 to 2.5 inches. Produces characteristic open, pyramidal panicle seed heads at maturity.
Blade Characteristics
Blades are medium-narrow (2-4mm wide), flat to folded with prominent parallel veins and distinctive boat-shaped tips. Vernation is folded in the bud. Features a short membranous ligule, and lacks auricles.
Root System
Moderately deep fibrous root system combined with strong spreading rhizomes. Forms a very tough, dense sod. Moderate establishment speed from seed, but excellent recovery from wear due to rhizomatous spread.
Growing Information
Origin Region
Native to Europe, northern Asia, and parts of North America. Widely cultivated throughout the northern United States, Canada, and cool temperate regions worldwide.
Growth Habit
Rhizomatous, spreading underground via robust horizontal roots to form a dense, uniform turf mat.
Sunlight & Water Needs
Requires full sun (at least 6-8 hours daily), though some cultivars show moderate shade tolerance. High water requirements to maintain active growth during summer heat. Good cold-weather dormancy survival, enters summer dormancy if severely drought-stressed.
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.5 inches. High maintenance requirement, needing regular fertilization (3-4 lbs N per 1000 sq ft annually), frequent irrigation during dry spells, and occasional dethatching and core aeration.
Special Characteristics
Exceptional wear tolerance and self-repairing capability via rhizomes. Good winter color retention in milder cool climates. Susceptible to certain diseases like dollar spot, leaf spot, and summer patch under stress.
Ecological Information
Introduced species in North America widely naturalized in cool climates. Provides standard turf ecosystem services such as soil stabilization, carbon sequestration, and cooling effects, with minimal native wildlife food value compared to native prairies.