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
General species type, common mixed cultivars adapted to northern lawns
Hardiness Zones
USDA Hardiness Zones 3 through 7, highly cold-tolerant but struggles in intense, humid heat without irrigation.
About This Grass
Forms a dense, medium-fine turf with a rich dark green to blue-green color. Reaches 18 to 24 inches if left unmowed, but maintained at 2 to 3 inches. Shows winter dormancy and turns brown under severe drought stress unless irrigated.
Blade Characteristics
Medium width (2-4mm), flat to folded with prominent parallel veins and distinctive boat-shaped tips. Folded in the bud (vernation). Short membranous ligule with no auricles.
Root System
Moderately deep fibrous root system with extensive underground rhizomes that provide excellent self-repair capabilities and form a tough, dense sod. Moderate to high thatch tendency.
Growing Information
Origin Region
Europe and northern Asia; widely naturalized and cultivated across North America and temperate regions worldwide
Growth Habit
Aggressively rhizomatous, forming a dense, uniform sod
Sunlight & Water Needs
Requires full sun for best performance (minimum 6 hours direct sunlight), moderate to high water needs, and enters dormancy during prolonged drought. Prefers well-drained fertile soils with a pH of 6.0 to 7.0.
Mowing & Maintenance
Maintain at 2.0 to 3.0 inches. Requires moderate to high maintenance, regular fertilization (3-5 lbs N per 1000 sq ft annually), frequent mowing, and periodic dethatching and aeration.
Special Characteristics
Excellent wear tolerance and superior ability to recover from damage via rhizomes. Moderate shade tolerance compared to fescues. Susceptible to certain diseases like dollar spot and leaf spot under high humidity.
Ecological Information
Introduced species in North America. Provides low to moderate wildlife value compared to native prairie grasses, primarily serving as grazing cover for small mammals and nesting habitat. Often blended with perennial ryegrass and fine fescues.