Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf, Golf Course Grass
Variety / Cultivar
Likely a blend such as 'Midnight' or 'Prosperity' based on the dark green color and high density
Hardiness Zones
USDA Zones 2-7; excellent cold tolerance, poor heat tolerance compared to warm-season grasses. Enters semi-dormancy in mid-summer heat and full dormancy in winter.
About This Grass
A high-quality turfgrass with a rich dark green to blue-green color. It forms a lush, dense carpet that is soft to the touch. It typically reaches 12-24 inches if unmowed, producing tiny, open panicle seed heads in late spring.
Blade Characteristics
Fine to medium width (2-4mm), folded in the bud (folded vernation). The most distinctive feature is the boat-shaped (keeled) leaf tip and a smooth surface with a prominent mid-rib. Ligule is short and membranous; auricles are absent.
Root System
Relatively shallow compared to fescues, but forms a thick network of rhizomes that creates a durable sod and allows for excellent recovery from damage. High thatch tendency due to rhizome density.
Growing Information
Origin Region
Native to Europe, North Asia, and the mountains of Algeria and Morocco; highly adapted to cool, humid climates in North America.
Growth Habit
Rhizomatous (spreading underground), forming a dense, uniform sod with a moderate rate of spread.
Sunlight & Water Needs
Full sun preferred (needs at least 6-8 hours); moderate shade tolerance in some cultivars. High water requirement; goes dormant during severe drought but can recover when water returns. Prefers well-drained soil with pH 6.0-7.5.
Mowing & Maintenance
Ideal height 2.0-3.5 inches. High maintenance level; requires regular fertilization (3-5 lbs N per 1000 sq ft/year), frequent mowing, and periodic dethatching/core aeration.
Special Characteristics
Excellent traffic and wear tolerance due to self-repairing rhizomes. Superior winter hardiness. Susceptible to summer diseases like brown patch or dollar spot if over-watered in heat.
Ecological Information
Introduced and naturalized in North America. Provides soil stabilization and erosion control. Offers food for various moth larvae and cover for small birds. Often mixed with Perennial Ryegrass or Fine Fescue for better resilience.