Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Common variant (visible mixed with broadleaf weed)
Hardiness Zones
USDA Hardiness Zones 2 through 7; excellent cold tolerance but poor heat tolerance in the Deep South.
About This Grass
A fine to medium textured grass with a rich dark green to blue-green color. It forms a lush, uniform turf and goes dormant during hot, dry summer periods. Seed heads are open, airy panicles with a pyramid shape.
Blade Characteristics
Blade width is medium (2-4mm), folded in the bud (folded vernation). The most distinguishing feature is the boat-shaped (keeled) leaf tip. Ligule is short and membranous; auricles are absent.
Root System
Relatively shallow but dense fibrous root system supplemented by strong rhizomes. Highly effective at forming thick sod and recovering from wear, though prone to thatch buildup.
Growing Information
Origin Region
Native to Europe, North Asia, and the mountains of Morocco and Algeria; widely adapted to temperate climates worldwide.
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense, sod-forming mat.
Sunlight & Water Needs
Prefers full sun (minimum 6 hours) but has moderate shade tolerance. High water requirements; requires supplemental irrigation in summer to avoid dormancy.
Mowing & Maintenance
Ideal height of 2.5 to 3.5 inches. High maintenance: requires regular fertilization (3-5 lbs N/1000 sq ft/year) and periodic core aeration to manage thatch.
Special Characteristics
Excellent self-repair capacity due to rhizomes. Good traffic tolerance once established. Susceptible to leaf spot, melting out, and necrotic ring spot under stress.
Ecological Information
Introduced species in North America. Provides soil stabilization and filtration. While widely used in landscaping, it can escape into wild meadows; often blended with Perennial Ryegrass or Fine Fescue.