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 dense growth)
Hardiness Zones
USDA Hardiness Zones 3-7. Excellent cold tolerance, enters winter dormancy. Can struggle in extreme summer heat of the deep south without heavy irrigation.
About This Grass
Forms a dense, high-quality turf with a medium-fine texture. Reaches 18-24 inches if unmoved but maintained at 1.5-2.5 inches. Color ranges from medium to dark blue-green. Produces open, pyramidal panicle seed heads at maturity.
Blade Characteristics
Blades are medium-narrow (2-4mm wide), flat to folded with prominent parallel veins and distinctive boat-shaped tips. Vernation is folded in the bud. Ligule is short and membranous, auricles absent.
Root System
Moderately deep fibrous root system with extensive branching rhizomes. Tends to build moderate thatch over time. Establishes slowly from seed, but creates an extremely tough, wear-resistant sod.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America and temperate regions worldwide
Growth Habit
Rhizomatous, spreading vigorously via underground stems to form a dense, uniform turf
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily); poor shade tolerance. Moderate to high water needs; enters dormancy during severe drought but recovers well when irrigated. Prefers fertile, well-drained soils with pH 6.0-7.0.
Mowing & Maintenance
Maintain at 2.0 to 3.0 inches. Medium to high maintenance level. Requires regular fertilization (3-4 lbs N per 1000 sq ft annually), periodic dethatching, and core aeration.
Special Characteristics
Exceptional wear tolerance and self-repairing capability via rhizomes. Good resistance to many common turf diseases, though susceptible to summer patch and leaf spot. Excellent winter color retention in cooler climates.
Ecological Information
Introduced species in North America. Provides good soil stabilization and erosion control due to dense root and rhizome matrix. Commonly blended with Perennial Ryegrass and Fine Fescues for home lawns.