Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae
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, goes into summer dormancy during extended hot and dry periods.
About This Grass
Forms a dense, lush, medium-fine textured turf with a vibrant dark green to blue-green color. Reaches 1.5 to 2 feet tall if unmowed, but maintained lawns are kept at 1.5 to 2.5 inches. Produces open, pyramidal panicle seed heads at maturity.
Blade Characteristics
Medium-fine width (2-4mm), flat to folded shape with distinctive boat-shaped tips, dark green to blue-green color, folded vernation in the bud, prominent parallel veins with a noticeable midrib, short membranous ligule, and absent auricles.
Root System
Moderately deep fibrous root system combined with extensive underground rhizomes, moderate establishment speed, forms a very dense sod, moderate thatch-forming tendency.
Growing Information
Origin Region
Europe and Northern Asia; widely cultivated across North America, Europe, and northern Asia in temperate climates
Growth Habit
Aggressively rhizomatous, forming a dense, uniform sod with underground spreading stems
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily), moderate to high watering needs for optimal appearance, moderate drought tolerance (enters dormancy during severe dry spells), prefers well-drained fertile soils with a pH of 6.0 to 7.0.
Mowing & Maintenance
Ideal mowing height of 2.0 to 3.0 inches, frequent mowing during active spring and fall growth, high fertilization requirement (3-5 lbs N per 1000 sq ft per year), regular dethatching and core aeration needed, high maintenance level.
Special Characteristics
Excellent traffic and wear tolerance due to aggressive self-repairing rhizomes, good cold and winter hardiness, moderate shade tolerance, slow to germinate from seed, forms a premium high-quality residential and athletic turf.
Ecological Information
Introduced species in North America, provides standard turf ecosystem benefits, helps prevent soil erosion through dense root and rhizome mat, commonly blended with perennial ryegrass and fine fescues.