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
Standard commercial blend (e.g., 'Midnight', 'Bewitched')
Hardiness Zones
USDA Hardiness Zones 3 through 7, with good cold tolerance down to -30F or lower, but struggles under extreme, prolonged summer heat without adequate irrigation.
About This Grass
Forms a dense, high-quality turf with a rich dark green to blue-green color. Mown height typically 1.5 to 2.5 inches, while unmowed growth can reach 18 to 24 inches with open, pyramidal panicle seed heads.
Blade Characteristics
Medium-fine width (2-3mm), flat to folded shape with distinctive boat-shaped tips. Vernation is folded in the bud. Smooth texture with prominent parallel veins and a slight keel. Ligule is short and membranous; auricles are absent.
Root System
Moderately deep fibrous root system combined with vigorous rhizomes. High tendency to form thatch if over-fertilized. Moderate establishment speed from seed, but excellent long-term wear recovery.
Growing Information
Origin Region
Europe, northern Asia, and parts of the mountainous regions of North America; widely cultivated throughout cool and transitional temperate regions globally.
Growth Habit
Aggressively rhizomatous, forming a dense sod and spreading underground via extensive root systems.
Sunlight & Water Needs
Performs best in full sun, requiring a minimum of 4-6 hours of direct sunlight. Moderate to high water needs; goes into summer dormancy during severe drought but recovers well with irrigation. Prefers fertile, well-drained soil with a pH between 6.0 and 7.0.
Mowing & Maintenance
Ideal mowing height ranges from 2.0 to 3.0 inches. Medium to high maintenance level, requiring regular mowing, 2 to 4 lbs of nitrogen per 1000 sq ft annually, and periodic dethatching/aeration.
Special Characteristics
Excellent traffic and wear tolerance due to aggressive rhizomatous spreading. Susceptible to certain diseases like dollar spot, leaf spot, and summer patch, but offers good winter color retention in milder cool-season climates.
Ecological Information
Introduced species in North America widely used for erosion control and turf stabilization. Provides limited wildlife value primarily as a grazing source. Frequently blended with perennial ryegrass and fine fescues.