Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf, Erosion Control
Variety / Cultivar
Common or mixed turf cultivars (e.g., 'Midnight', 'Bewitched')
Hardiness Zones
USDA Hardiness Zones 3 to 7, excellent cold tolerance, moderate heat tolerance, goes into summer dormancy during extended hot and dry periods.
About This Grass
Forms a dense, medium-textured turf with a rich dark green to blue-green color. Matured plants can reach 18 to 24 inches if unmowed, but maintained lawns are kept at 1.5 to 3 inches. Produces open, pyramidal panicle seed heads.
Blade Characteristics
Medium blade width (2-4mm), folded vernation in the bud, boat-shaped tip, smooth texture with prominent parallel veins creating a railroad-track appearance. Membranous ligule, absent auricles.
Root System
Moderately deep fibrous root system combined with extensive rhizomes. Moderate establishment speed, moderate thatch-forming tendency under high fertilization, excellent wear recovery due to spreading rhizomes.
Growing Information
Origin Region
Europe and northern Asia; widely naturalized and cultivated throughout North America, particularly in the northern and transition zones.
Growth Habit
Rhizomatous, spreading underground via aggressive creeping rhizomes to form a dense, uniform turf mat.
Sunlight & Water Needs
Full sun is preferred (minimum 6 hours of direct sunlight), moderate to high water requirements to maintain green color during summer heat, moderate drought tolerance through summer dormancy, prefers well-drained fertile soils with a pH of 6.0 to 7.0.
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.5 inches. Requires regular mowing weekly during peak growing seasons. Fertilization needs are medium to high (3-4 lbs N per 1000 sq ft annually). Requires periodic dethatching and core aeration. Medium-high maintenance level.
Special Characteristics
Good traffic and wear tolerance due to rhizomatous spread, moderate disease susceptibility (susceptible to dollar spot, leaf spot, and summer patch), good drought recovery, excellent winter color retention in milder climates, strong weed-crowding ability.
Ecological Information
Introduced species in North America. Provides good soil stabilization and erosion control due to dense sod formation. Frequently blended with Perennial Ryegrass and Fine Fescue for home lawns and athletic fields.