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, Erosion Control
Variety / Cultivar
Common or mixed turf type cultivars (e.g., 'Midnight', 'Baron')
Hardiness Zones
USDA Hardiness Zones 3 to 7, excellent cold tolerance, goes semi-dormant during extreme summer heat, well-suited to the northern US and cooler transition zones.
About This Grass
Forms a lush, dense turf with medium-fine texture and a rich dark green to blue-green color. Reaches up to 18-24 inches if unmowed, but maintained at 1.5-2.5 inches. Develops open, pyramidal panicle seed heads at maturity.
Blade Characteristics
Blades are medium-narrow (3-4mm), flat or folded with distinct parallel veins and characteristic boat-shaped (prow-like) tips. Vernation is folded in the bud. Ligule is short and membranous; auricles are absent.
Root System
Moderately deep fibrous root system with extensive branching rhizomes. Forms a very tough, dense sod. Tends to build thatch under high fertility and watering. Moderate establishment speed from seed.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America and temperate regions worldwide, performing best in cool, humid and transition zones.
Growth Habit
Aggressively rhizomatous, spreading via underground stems to form a dense, uniform turf mat and sod.
Sunlight & Water Needs
Requires full sun (at least 6-8 hours daily), moderate to high watering needs, moderate drought tolerance (goes dormant in severe drought), prefers well-drained fertile soils with a pH of 6.0-7.0.
Mowing & Maintenance
Mow at 1.5 to 2.5 inches. Requires regular fertilization (2-4 lbs N per 1000 sq ft annually), periodic dethatching and core aeration. Maintenance level is medium to high.
Special Characteristics
Exceptional wear tolerance and self-repairing capability via rhizomes. Good winter color retention in milder cool-season areas. Moderate shade tolerance compared to fescues. Recovers well from dormancy.
Ecological Information
Introduced species in North America. Provides good soil stabilization and erosion control due to dense root and rhizome matrix. Commonly blended with perennial ryegrass and fine fescues.