Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf
Variety / Cultivar
Common or mixed turf cultivars (e.g., 'Midnight', 'Baron')
Hardiness Zones
Thrives in USDA Hardiness Zones 3 to 7; excellent cold tolerance, goes dormant and turns straw-colored under severe drought or extreme heat.
About This Grass
Forms a dense, medium-textured turf with an attractive rich green to dark green color. Reaches 18 to 24 inches if left unmowed, but maintained at 1.5 to 2.5 inches. Produces open, pyramidal panicle seed heads at maturity.
Blade Characteristics
Medium-fine width (2-4mm), folded in the bud (vernation), with distinctive boat-shaped tips and prominent parallel parallel veins giving a railroad-track appearance. Ligule is short and membranous; auricles are absent.
Root System
Moderately deep fibrous root system combined with aggressive rhizomes, creating a very dense sod. Moderate to slow establishment speed from seed, but excellent recovery from wear via rhizomes.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America and temperate regions worldwide.
Growth Habit
Rhizomatous, spreading extensively via underground creeping stems to form a dense, uniform turf mat.
Sunlight & Water Needs
Requires full sun (at least 6-8 hours daily), moderate to high water needs to maintain green color during summer, moderate drought tolerance by entering summer dormancy, prefers well-drained fertile soils with a pH of 6.0-7.0.
Mowing & Maintenance
Ideal mowing height is 1.5 to 2.5 inches. High maintenance level requiring regular fertilization (3-4 lbs N/1000 sq ft/year), frequent watering, periodic aeration, and dethatching due to dense sod formation.
Special Characteristics
Exceptional wear tolerance and self-repairing capability due to rhizomes. Moderate shade tolerance compared to fine fescues. Good cold and winter tolerance.
Ecological Information
Introduced species in North America. Provides good soil stabilization and erosion control due to dense root and rhizome network. Often blended with perennial ryegrass and fine fescues in turf seed mixes.