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
Midnight (known for dark blue-green color and high density)
Hardiness Zones
USDA Hardiness Zones 3 to 7; excellent cold tolerance, moderate heat tolerance; standard cool-season turf grass across northern climates and parts of the transition zone
About This Grass
Forms a dense, high-quality turf with a medium-fine texture and rich blue-green color; maintains color well in cool weather but can go dormant in extreme summer heat or drought; grows 1.5 to 2.5 feet tall if unmowed, but maintained at 2 to 3 inches.
Blade Characteristics
Medium-fine width (2-4mm), boat-shaped tips, folded vernation in the bud, V-shaped cross section with prominent parallel veins on the upper surface giving a tramline appearance; membranous ligule, absent auricles
Root System
Moderately deep fibrous root system combined with vigorous rhizomes; moderate establishment speed from seed; forms a very tough, dense sod that excellent for wear recovery
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America and temperate regions worldwide
Growth Habit
Rhizomatous, spreading extensively via underground stems to form a dense, uniform turf mat
Sunlight & Water Needs
Full sun preferred (minimum 6 hours of direct sunlight); moderate to high water requirements; moderate drought tolerance by entering summer dormancy; prefers well-drained, fertile soils with a pH of 6.0 to 7.0
Mowing & Maintenance
Ideal mowing height ranges from 2.0 to 3.0 inches; requires regular mowing during peak growth seasons; medium-high fertilization needs (3-4 lbs N per 1000 sq ft annually); moderate thatch tendency requiring occasional dethatching or aeration; high overall maintenance level
Special Characteristics
High wear tolerance and exceptional self-repair capability via rhizomes; good resistance to many common turf diseases, though susceptible to summer patch and dollar spot; excellent erosion control and weed suppression due to density
Ecological Information
Introduced species in North America; provides standard urban wildlife habitat and good soil stabilization/filtration qualities; commonly blended with Perennial Ryegrass and Fine Fescues in northern lawn seed mixtures