Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Common or 'Midnight' type (typical characteristics visible)
Hardiness Zones
USDA Zones 2-7; excellent cold tolerance; enters dormancy (browns) during summer heat or winter freezes.
About This Grass
A dark green to blue-green grass with a dense, fine-to-medium texture. It produces a soft lawn surface and features narrow blades that bow slightly. In the wild, it grows 12-36 inches but is kept short in lawns.
Blade Characteristics
Fine to medium width (2-4mm), V-shaped or flat; distinctive boat-shaped (keeled) tip; dark green color; folded vernation; membranous ligule; no auricles.
Root System
Relatively shallow but extensive fibrous root system reinforced by underground rhizomes; moderate thatch tendency; slow establishment compared to ryegrass.
Growing Information
Origin Region
Native to Europe and Northern Asia; widely naturalized in North America and adapted to cool, humid climates.
Growth Habit
Rhizomatous (spreading underground), forming a dense sod over time despite the mixed-species appearance in the image.
Sunlight & Water Needs
Full sun preferred (requires 6+ hours); moderate to high watering needs; goes dormant during drought but has high recovery ability; prefers pH 6.0-7.0.
Mowing & Maintenance
High maintenance; ideal height 2.5-3.5 inches; requires regular fertilization (2-4 lbs N/1000 sq ft/year); benefits from annual aeration.
Special Characteristics
Excellent traffic recovery due to rhizomes; high aesthetic quality; fair shade tolerance (cultivar dependent); susceptible to leaf spot and dollar spot.
Ecological Information
Introduced/Naturalized in US; provides forage for various insects and small mammals; often mixed with Fine Fescue or Perennial Ryegrass; visible here with Trifolium repens (White Clover).