Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
AI-generated identification · may be incorrect
Grass Category
Lawn/Turf Grass, Sports Turf, Erosion Control
Hardiness Zones
USDA Hardiness Zones 3 through 7, highly cold tolerant, exhibits winter dormancy, and struggles in extreme prolonged summer heat outside the transition zone.
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Variety / Cultivar
Common blend (such as 'Midnight' or 'Compact Midnight' types often used in northern lawns)
About This Grass
Forms a lush, dense turf with a rich dark green to blue-green color. Mown height typically maintained at 2 to 3.5 inches, while unmowed height can reach 18 to 24 inches with open, pyramidal panicle seed heads.
Blade Characteristics
Medium-fine width (2 to 4 mm), flat to V-shaped blades with distinctive boat-shaped tips and parallel veins. Folded vernation in the bud, short membranous ligule, and lacking auricles.
Root System
Moderately deep fibrous root system combined with extensive underground rhizomes. Moderate establishment speed, forms a very tough and dense sod, and exhibits a moderate tendency to build thatch.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America, performing best in northern cool-temperate regions
Growth Habit
Aggressively rhizomatous, forming a dense, uniform turf mat and strong sod
Sunlight & Water Needs
Requires full sun (at least 6 hours of direct sunlight) for optimal performance, though some varieties have moderate shade tolerance. High water needs during dry spells, goes into summer dormancy if unwatered, and prefers well-drained loamy soils with a pH of 6.0 to 7.0.
Mowing & Maintenance
Ideal mowing height ranges from 2.0 to 3.5 inches. Requires regular mowing, medium to high fertilization (3 to 4 lbs N per 1000 sq ft annually), periodic dethatching and core aeration, and falls under a high-maintenance category.
Special Characteristics
Excellent traffic and wear tolerance due to aggressive rhizome regeneration, moderate disease resistance (susceptible to dollar spot and leaf spot under stress), very good winter color retention in milder cool climates, and forms an excellent weed-crowding sod.
Ecological Information
Introduced species in North America, provides basic urban wildlife cover, excellent soil stabilization through its dense sod and rhizomes, filters runoff effectively, and is commonly blended with Perennial Ryegrass and Fine Fescue.