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 turf-type cultivars (e.g., 'Midnight', 'Bewitched')
Hardiness Zones
Thrives in USDA Hardiness Zones 3 through 7, performing exceptionally well in northern regions and parts of the upper transition zone. Exhibits excellent cold tolerance.
About This Grass
Forms a dense, high-quality turf with a medium-fine texture and rich dark-green to blue-green color. Mowed height is typically 1.5 to 2.5 inches, while unmowed height can reach 18 to 24 inches with open, pyramidal panicle seed heads.
Blade Characteristics
Medium width (3-4mm), flat to folded with prominent parallel veins and a classic boat-shaped tip. Vernation is folded in the bud. Ligule is short and membranous, and auricles are absent.
Root System
Moderately deep fibrous root system combined with extensive underground rhizomes. Tends to form a moderate amount of thatch if over-fertilized. Establishes slowly from seed.
Growing Information
Origin Region
Europe, Northern Asia, and parts of North Africa; widely naturalized and cultivated across North America and cool temperate regions globally
Growth Habit
Rhizomatous (spreading aggressively via underground stems), forming a dense, uniform sod
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily) and moderate to high moisture. Moderate drought tolerance, entering dormancy during prolonged dry spells. Prefers well-drained, fertile soils with a pH of 6.0 to 7.0.
Mowing & Maintenance
Maintain at 2.0 to 3.5 inches height. Requires regular mowing, moderate to high fertilization (3-4 lbs N per 1000 sq ft per year), periodic dethatching, and aeration. High overall maintenance level.
Special Characteristics
High wear tolerance and exceptional self-repair capability via rhizomes. Moderate shade tolerance (best in full sun). Susceptible to certain diseases like dollar spot and leaf spot under stress.
Ecological Information
Introduced species to North America. Provides good soil stabilization and erosion control due to dense root and rhizome matrix. Frequently blended with perennial ryegrass and fine fescues for lawns.