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, goes dormant in extreme summer heat.
About This Grass
Forms a dense, medium-textured turf with an upright growth habit. Height reaches 18 to 24 inches if left unmowed, but maintained at 1.5 to 2.5 inches. Color ranges from medium to dark blue-green. Produces pyramidal panicle seed heads at maturity.
Blade Characteristics
Medium width (2-4mm), flat to V-shaped with distinct boat-shaped tips and prominent parallel veins. Vernation is folded in the bud. Ligule is short and membranous, and auricles are absent.
Root System
Moderately deep fibrous root system combined with vigorous underground rhizomes. Forms a very dense sod, has moderate thatch-forming tendencies, and establishes relatively slowly from seed.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America and temperate regions worldwide
Growth Habit
Rhizomatous with aggressive underground spreading, forming a dense and uniform turf mat
Sunlight & Water Needs
Requires full sun (at least 6-8 hours daily) with good shade tolerance for certain modern cultivars. High watering needs during dry spells to stay green, goes into summer dormancy under severe drought. Prefers well-draining, fertile soils with a pH of 6.0 to 7.0.
Mowing & Maintenance
Mow at 1.5 to 2.5 inches regularly during peak growth. Requires moderate to high maintenance, including 2 to 4 lbs N per 1000 sq ft annually, regular irrigation, and periodic dethatching and aeration.
Special Characteristics
Excellent traffic and wear tolerance due to aggressive rhizomatous recovery. Good disease resistance when properly managed. High erosion control ability and forms a dense barrier against weeds.
Ecological Information
Introduced species in North America. Provides low wildlife forage value compared to native prairie grasses, but offers excellent soil stabilization and water filtration through its dense root and rhizome matrix. Commonly blended with Perennial Ryegrass and Tall Fescue.