Kentucky Bluegrass
Poa pratensis · Cool-season, perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf, Golf Course Grass, Erosion Control
Variety / Cultivar
General species type, widely used in blends like 'Midnight' or 'Bewitched'
Hardiness Zones
Thrives in USDA Hardiness Zones 3 through 7. Excellent cold tolerance, but struggles with extreme summer heat and humidity outside the northern transition zone.
About This Grass
Forms a dense, fine-to-medium textured turf with an attractive medium to dark blue-green color. Mown height typically ranges from 1.5 to 2.5 inches, while unmowed seed heads can reach 18 to 24 inches. Produces open, pyramidal panicle seed heads in late spring.
Blade Characteristics
Blades are medium-narrow (2-4mm wide), flat to folded with prominent parallel veins and characteristic boat-shaped (prow-like) tips. Vernation is folded in the bud. Ligule is short and membranous, with auricles typically absent.
Root System
Moderately deep fibrous root system combined with an extensive rhizome network. Forms a very dense sod, moderate to high thatch tendency, and slow to moderate establishment speed from seed.
Growing Information
Origin Region
Native to Europe, northern Asia, and the mountains of northern North America. Extensively cultivated across the northern United States, Canada, and cool regions worldwide.
Growth Habit
Aggressively rhizomatous, spreading underground via robust rhizomes to form a dense, uniform, self-repairing turf mat.
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily) for best performance, though some cultivars offer moderate shade tolerance. High water needs to maintain green color during summer; goes into summer dormancy under severe drought conditions.
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.0 inches. Medium to high maintenance level requiring regular fertilization (2-4 lbs N per 1000 sq ft annually), frequent watering, periodic aeration, and dethatching.
Special Characteristics
Exceptional wear tolerance and self-repair capability due to rhizomes. Good cold hardiness and winter color retention in milder cool regions. Moderate tolerance to traffic and disease (susceptible to dollar spot and leaf spot under stress).
Ecological Information
Widely naturalized in North America. Provides good soil stabilization and erosion control due to its dense root and rhizome matrix. Frequently blended with Perennial Ryegrass and Fine Fescues for residential and commercial turf.