Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf, Golf Course Grass
Variety / Cultivar
Common or various blended turf cultivars (e.g., 'Midnight', 'Bewitched')
Hardiness Zones
Thrives in USDA Hardiness Zones 3 through 7, tolerating cold winters well but struggling in intense, humid heat without irrigation.
About This Grass
Forms a dense, fine-to-medium textured lawn with a vibrant medium to dark green color. Height ranges from 1.5 to 2.5 inches when maintained, but can reach 18-24 inches if left unmowed. Produces open, pyramidal panicle seed heads at maturity.
Blade Characteristics
Blades are medium-narrow (2-4mm), flat to folded, with distinctive boat-shaped tips and prominent parallel veins giving a railroad-track appearance. Vernation is folded in the bud. Ligule is short and membranous; auricles are absent.
Root System
Moderately deep fibrous root system combined with strong rhizomes. Forms a dense sod, has a moderate to high tendency to produce thatch, and establishes relatively slowly from seed.
Growing Information
Origin Region
Europe and northern Asia; widely naturalized and cultivated across North America and cool-temperate regions worldwide.
Growth Habit
Rhizomatous, forming a dense, uniform sod through extensive underground spreading stems.
Sunlight & Water Needs
Requires full sun (at least 6-8 hours daily) for optimal performance; moderate to high water needs during hot periods; goes into summer dormancy under severe drought conditions. Prefers well-drained, fertile soils with a pH between 6.0 and 7.0.
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.5 inches. Requires frequent mowing during peak spring/fall growth. High fertilizer requirement (3-4 lbs N per 1000 sq ft annually). Moderate to high maintenance level.
Special Characteristics
Excellent traffic and wear tolerance due to aggressive rhizomatous recovery, good cold hardiness, moderate disease susceptibility (e.g., dollar spot, leaf spot), poor shade tolerance.
Ecological Information
Introduced species in North America; provides soil stabilization, erosion control, and turf cover; frequently mixed with perennial ryegrass and fine fescues in seed blends for lawns and athletic fields.