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 Elite-type Kentucky Bluegrass (e.g., 'Midnight' or 'Baron' styles)
Hardiness Zones
USDA Zones 2-7; excellent cold tolerance; limited heat tolerance (enters dormancy above 90°F); primary grass of the northern United States.
About This Grass
A medium-textured, high-density turfgrass with a soft feel. It exhibits a deep emerald to blue-green color. When mowed, it creates a uniform carpet; if left unmowed, it can reach 12-24 inches with open, airy panicle seed heads.
Blade Characteristics
Blade width is medium (2-4mm); flat or slightly folded; features a characteristic 'boat-shaped' (V-shaped) tip. Color is rich blue-green; vernation is folded in the bud; ligule is short and membranous; auricles are absent.
Root System
Moderately shallow fibrous root system with extensive rhizomes. The rhizomes allow for excellent thatch formation and sod knitting; establishment is slow (21 days for germination) but yields high wear recovery.
Growing Information
Origin Region
Native to Europe, North Asia, and North Africa; widely naturalized across North America, performing best in cool-humid and cool-arid regions.
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense, self-repairing sod; growth rate is moderate.
Sunlight & Water Needs
Requires Full Sun (6+ hours) for best performance; has moderate shade tolerance. High water needs to maintain green color; enters semi-dormancy during extreme heat/drought to survive.
Mowing & Maintenance
Ideal height of 2.0-3.5 inches. High maintenance: requires 2-4 lbs of nitrogen per 1000 sq ft annually, regular dethatching, and consistent irrigation.
Special Characteristics
Excellent traffic/wear tolerance due to rhizomes; high aesthetic value; susceptible to summer patch and necrotic ring spot; high salt sensitivity; excellent winter hardiness.
Ecological Information
Introduced/Naturalized status; provides soil stabilization via dense sod; common companion grass for Perennial Ryegrass and Fine Fescue in 'Northern Mixes'.