Kentucky Bluegrass
Poa pratensis · Cool-season, perennial, C3 grass
AI-generated identification · may be incorrect
Grass Category
Lawn/Turf Grass and Sports Turf
Hardiness Zones
USDA Hardiness Zones 3 through 7; exhibits excellent cold tolerance but can go summer dormant or suffer in prolonged extreme heat without irrigation
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Variety / Cultivar
Common blend, often including cultivars like 'Midnight' or 'America'
About This Grass
Forms a dense, high-quality turf with a vibrant medium-to-dark green color; typically maintained at 1.5 to 2.5 inches, but can reach 18-24 inches if unmowed; fine-to-medium texture with excellent wear recovery due to aggressive rhizome expansion
Blade Characteristics
Medium-narrow blades (2-4 mm) with characteristic boat-shaped tips, folded vernation in the bud, prominent parallel veins creating a railroad-track appearance, membranous ligule, and absent auricles
Root System
Moderately deep fibrous root system combined with vigorous rhizomes; forms a very dense sod, has moderate thatch-forming tendencies, and establishes relatively slowly from seed compared to ryegrass
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 sod
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily) for optimal growth, moderate to high water needs to maintain green color during summer, good cold-induced winter dormancy, and prefers well-drained loamy soils with a pH of 6.0 to 7.0
Mowing & Maintenance
Mow at 2.0 to 3.0 inches, frequent mowing during peak spring growth; requires moderate to high fertilization (3-4 lbs N per 1000 sq ft annually); regular aeration and occasional dethatching needed; high maintenance level
Special Characteristics
Excellent traffic and wear tolerance due to aggressive self-repairing rhizomes, good cold tolerance, moderate disease susceptibility (susceptible to dollar spot, leaf spot, and summer patch), poor shade tolerance compared to fescues
Ecological Information
Introduced species in North America; provides standard lawn ecosystem functions and soil stabilization; often blended with perennial ryegrass and fine fescues for lawns and athletic fields