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 Fairways
Variety / Cultivar
Common blend, often mixes of cultivars like 'Midnight' or 'Baron'
Hardiness Zones
USDA Hardiness Zones 3 to 7. Excellent cold tolerance, goes semi-dormant or fully dormant in extreme cold. Struggles in deep southern heat zones without intensive irrigation.
About This Grass
Forms a dense, high-quality turf with a medium-fine texture and rich green to blue-green color. Reaches 18 to 24 inches if left unmowed, but typically maintained at 1.5 to 2.5 inches. Produces panicle seed heads in late spring.
Blade Characteristics
Medium-fine width (2-4mm), flat to folded with prominent parallel veins and distinctive boat-shaped tips. Vernation is folded in the bud. Ligule is short and membranous; auricles are absent.
Root System
Moderately deep fibrous root system combined with aggressive underground rhizomes. Forms a very tough, dense sod. Moderate to fast establishment speed from seed; high tendency to form thatch if over-fertilized.
Growing Information
Origin Region
Europe and northern Asia; widely naturalized and cultivated throughout the northern United States, Canada, and cool temperate regions worldwide.
Growth Habit
Rhizomatous, spreading vigorously via underground stems to form a dense, uniform turf mat.
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily) for best performance, though some cultivars show moderate shade tolerance. High water needs during hot, dry periods to prevent dormancy; goes dormant during severe drought and greens up upon re-watering.
Mowing & Maintenance
Mow at 2.0 to 3.0 inches. Medium to high maintenance level. Requires regular fertilization (3-4 lbs N per 1000 sq ft per year), periodic dethatching and core aeration, and regular irrigation during dry spells.
Special Characteristics
Exceptional wear tolerance and self-repairing capability due to rhizomes. Good cold tolerance, moderate drought dormancy, fair shade tolerance depending on cultivar. Susceptible to certain diseases like leaf spot, dollar spot, and summer patch.
Ecological Information
Introduced species in North America. Provides good soil stabilization, erosion control, and urban green space benefits. Frequently blended with Perennial Ryegrass and Fine Fescues in northern lawn seed mixtures.