Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae
Grass Category
Lawn/Turf Grass, Sports Turf
Variety / Cultivar
Standard turf-type blends (e.g., 'Midnight', 'Baron')
Hardiness Zones
USDA Hardiness Zones 3-7, performs exceptionally well in northern climates and the northern transition zone.
About This Grass
Forms a dense, high-quality turf with a medium-fine texture and rich medium to dark green color. Reaches up to 18-24 inches if left unmowed but is typically maintained at 2-3.5 inches. Can go dormant and turn brown during severe summer heat and drought.
Blade Characteristics
Medium-fine width (2-4mm), flat to V-shaped blades with distinct boat-shaped tips and prominent parallel veins giving a tramline appearance. Vernation is folded in the bud. Ligule is short and membranous, with no auricles.
Root System
Moderately deep fibrous root system combined with vigorous rhizomes. Establishes slowly from seed, but creates a dense, tough sod with high wear recovery once mature. Moderate to high thatch-forming tendency.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America and temperate regions worldwide
Growth Habit
Rhizomatous, spreading extensively via underground stems to form a dense, uniform sod
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily) though has moderate shade tolerance depending on the cultivar. High water needs to maintain lush green color during peak summer. Tolerates moderate drought by entering dormancy.
Mowing & Maintenance
Mow at 2.0 to 3.5 inches every 5-7 days during active growth. Requires medium to high maintenance, needing 2-4 lbs of nitrogen per 1000 sq ft annually, regular irrigation, and periodic dethatching/aeration.
Special Characteristics
Excellent self-repairing wear tolerance due to aggressive rhizomes. Good cold tolerance and winter color retention in milder winter zones. Susceptible to diseases like summer patch, dollar spot, and leaf spot under high humidity and improper fertilization.
Ecological Information
Introduced species in North America. Provides good soil stabilization and erosion control due to dense turf mat. Frequently blended with Perennial Ryegrass and Fine Fescues to improve disease resistance and establishment speed.