Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Common or 'Midnight' type blend
Hardiness Zones
USDA Hardiness Zones 2 to 7; excellent cold tolerance; goes dormant and turns brown during extreme summer heat or drought.
About This Grass
A dense, low-growing turf grass known for its dark green to blue-green color. It forms a lush carpet that spreads horizontally via rhizomes. When unmowed, it produces panicle-type seed heads resembling small, open pyramids.
Blade Characteristics
Fine to medium width (2-4mm); characteristic boat-shaped (keeled) tip; V-shaped or flat cross-section; folded vernation; membranous ligule; no auricles.
Root System
Relatively shallow fibrous root system with extensive horizontal rhizomes; forms a tight sod but requires significant water in drought due to shallow roots; moderate thatch producer.
Growing Information
Origin Region
Native to Europe, Northern Asia, and the mountains of Morocco and Algeria; best adapted to cool, humid climates in North America.
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense, self-repairing sod.
Sunlight & Water Needs
Full sun preferred (needs 6+ hours); moderate to high water requirements; poor drought tolerance compared to fescues; prefers pH 6.0-7.5.
Mowing & Maintenance
Ideal height 2.5 to 3.5 inches; high maintenance; requires 2-4 lbs N per 1000 sq ft annually; requires regular aeration due to thatch buildup.
Special Characteristics
Excellent traffic recovery due to rhizomes; high turf quality and soft feel; susceptible to Summer Patch, Dollar Spot, and Necrotic Ring Spot.
Ecological Information
Introduced/Naturalized in North America; provides forage for various insects; often blended with Perennial Ryegrass or Fine Fescues. Frequently found mixed with White Clover (Trifolium repens), as seen in the provided image, which provides nitrogen fixation.