Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf
Variety / Cultivar
Common or mixed turf cultivars (e.g., 'Midnight', 'Bewitched')
Hardiness Zones
USDA Hardiness Zones 3 to 7 (thrives in northern and transition zones), excellent cold tolerance, moderate heat tolerance.
About This Grass
Forms a dense, high-quality turf with medium-fine texture and rich dark-to-medium green or blue-green color. Mown height typically maintained at 2 to 3 inches, while unmown plants can reach 18 to 24 inches with panicle seed heads.
Blade Characteristics
Medium width (3-4 mm), flat to slightly folded with parallel sides and characteristic boat-shaped tips. Vernation is folded in the bud. Ligule is short and membranous; auricles are absent. Visible parallel veins running the length of the blade.
Root System
Moderately deep fibrous root system combined with aggressive rhizomes, creating a dense sod. Moderate establishment speed from seed; prone to moderate thatch accumulation under high fertility.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America and cool temperate regions worldwide
Growth Habit
Rhizomatous, spreading extensively via underground stems to form a dense, uniform turf mat
Sunlight & Water Needs
Requires full sun (at least 6-8 hours daily); moderate to high water needs; moderate drought tolerance entering summer dormancy during severe dry spells; prefers well-drained fertile loam with pH 6.0-7.0.
Mowing & Maintenance
Mow at 2.0 to 3.5 inches every 5-7 days during active growth. High maintenance level requiring 2-4 lbs N per 1000 sq ft annually, regular irrigation, and periodic dethatching/aeration.
Special Characteristics
Good traffic and wear tolerance due to aggressive rhizome recovery; moderate disease susceptibility (leaf spot, dollar spot, summer patch); excellent winter color retention in milder cool zones.
Ecological Information
Introduced species in North America; provides standard lawn cover and minor wildlife foraging value; excellent for soil stabilization and erosion control on managed landscapes; frequently blended with perennial ryegrass and fescues.