Kentucky Bluegrass
Poa pratensis · Cool-season perennial, C3 pathway
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf, Golf Course Fairways
Variety / Cultivar
Common or Elite-type (e.g., 'Midnight' or 'Baron'), typically used in high-quality lawn blends
Hardiness Zones
USDA Zones 2-7; excellent cold tolerance, poor heat tolerance; goes dormant (straw-colored) in extreme heat or extreme cold.
About This Grass
A dense, cool-season turfgrass with a characteristic dark green or blue-green color. It exhibits a fine-to-medium texture and horizontal spread via rhizomes. When allowed to flower, it produces distinctive panicle-type seed heads resembling small trees.
Blade Characteristics
Blade width usually 2-4mm (medium); flat or slightly folded; uniquely 'boat-shaped' tips that resemble the bow of a canoe; vernation is folded in the bud; dark green color with a prominent midrib on the underside; ligule is short and membranous; auricles are absent.
Root System
Fibrous root system with extensive horizontal rhizomes; moderate depth (~6-12 inches); produces heavy thatch; slow to establish from seed but excellent for sod production and wear recovery.
Growing Information
Origin Region
Native to Europe and Northern Asia; widely naturalized and highly adapted to the Northern United States and Canada
Growth Habit
Rhizomatous (underground spreading stem); creates a dense, self-repairing sod mat
Sunlight & Water Needs
Full sun preferred (6-8+ hours), moderate shade tolerance; requires consistent moisture (~1-1.5 inches per week) and typically enters dormancy during extreme summer heat/drought.
Mowing & Maintenance
Recommended height: 2.0-3.5 inches; high maintenance level; requires 2-4 lbs Nitrogen per 1,000 sq ft annually; needs core aeration to manage thatch; frequent mowing required during spring/fall growth flush.
Special Characteristics
Excellent traffic/wear tolerance and recovery due to rhizomes; highly susceptible to Necrotic Ring Spot and Summer Patch in humid conditions; used on high-end athletic fields and home lawns for its lush feel.
Ecological Information
Introduced species; provides good soil stabilization on slopes; often blended with Perennial Ryegrass or Fine Fescue for biodiversity and disease resistance; can be slightly invasive in native prairie ecosystems.