Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf, Golf Course Grass
Variety / Cultivar
Common-type (or 'Midnight-type' based on deep green color and density)
Hardiness Zones
USDA Hardiness Zones 2-7; excellent cold tolerance. Enters dormancy (browns) in high heat/drought or extreme cold.
About This Grass
A medium-textured, high-density grass known for its dark green to blue-green color. It forms a lush carpet and reaches 12-24 inches if left unmowed. Features a panicle-shaped seed head that is open and pyramidal.
Blade Characteristics
Width: 2-4mm (medium); Shape: folded in the bud; Tip: distinct boat-shaped (keeled) tip; Color: dark green to blue-green; Ligule: short, membranous, and truncate; Auricles: absent; Collar: narrow and continuous.
Root System
Fibrous and rhizomatous; moderate depth (6-12 inches). High thatch-forming tendency due to rhizomes. Slow to moderate establishment speed but excellent sod-forming capability.
Growing Information
Origin Region
Europe, Northern Asia, and Northern Africa; widely naturalized in North America and cool-temperate regions worldwide
Growth Habit
Rhizomatous; spreads via underground stems to form a dense, uniform, and self-repairing sod.
Sunlight & Water Needs
Requires Full Sun (6+ hours) for best density; moderate shade tolerance. High water needs (1-1.5 inches per week). Excellent dormancy mechanism during extreme drought.
Mowing & Maintenance
Ideal height: 2.0-3.5 inches; Frequency: weekly during peak growth. Fertilization: 2-4 lbs N/1000 sq ft/year. High maintenance; requires periodic dethatching and aeration.
Special Characteristics
Excellent wear tolerance and recovery due to rhizomes. Susceptible to summer patch, dollar spot, and necrotic ring spot. Highly valued for aesthetic beauty and soft texture.
Ecological Information
Introduced and naturalized in North America. Provides erosion control and nesting cover for small birds. Often used in mixes with Perennial Ryegrass and Fine Fescue for balanced turf durability.