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
Variety / Cultivar
Common or mixed turf cultivars (e.g., 'Midnight', 'Bewitched')
Hardiness Zones
Thrives in USDA Hardiness Zones 3 through 7, excellent cold tolerance down to -30°F or lower, struggles with extreme summer heat unless irrigated.
About This Grass
Forms a rich, dark green to blue-green, highly dense turf with medium-fine texture. Height reaches 1.5 to 2 feet if unmowed, but maintained at 1.5 to 3 inches. Produces characteristic open, pyramidal panicle seed heads at maturity.
Blade Characteristics
Medium-fine width (2-3mm), flat to folded shape with distinctive boat-shaped tips and prominent parallel veins giving a railroad-track appearance. Vernation is folded in the bud. Ligule is short and membranous; auricles are absent.
Root System
Moderate depth (6-12 inches) with an extensive, fibrous root system and aggressive rhizomes. Can develop moderate thatch under high fertilization and watering. Establishes slowly from seed.
Growing Information
Origin Region
Europe, Northern Asia, and the mountains of North America; widely cultivated throughout northern North America, Europe, and cool regions globally.
Growth Habit
Rhizomatous, forming an aggressive underground network that creates a dense, tight sod and enables self-repair.
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily), moderate to high water needs for optimal appearance, enters summer dormancy during severe drought. Prefers well-drained, fertile soils with a pH between 6.0 and 7.0.
Mowing & Maintenance
Mowing height range of 2.0 to 3.5 inches. High maintenance level requiring regular fertilization (3-5 lbs N per 1000 sq ft annually), frequent irrigation, and occasional dethatching and core aeration.
Special Characteristics
Exceptional wear tolerance and excellent self-repair capabilities via rhizomes. Good cold tolerance and winter color retention in milder cool regions. Moderate disease susceptibility (e.g., dollar spot, leaf spot, summer patch).
Ecological Information
Widely naturalized and introduced in North America. Provides good soil stabilization and turf density that filters runoff. Often blended with Perennial Ryegrass and Fine Fescues to improve establishment and disease resistance.