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 Elite-type Kentucky Bluegrass (e.g., 'Midnight' or 'Baron' typical of residential lawns)
Hardiness Zones
USDA Zones 2-7; excellent cold tolerance, goes dormant and turns brown during extreme heat or freezing winter temperatures.
About This Grass
A medium-textured turf grass that forms a soft, dense carpet. It is known for its dark green to blue-green color and high aesthetic appeal. When left unmowed, it can reach 12-24 inches with distinctive 'boat-shaped' panicle seed heads.
Blade Characteristics
Blade width is medium (2-4mm), folded in the bud; the most identifying feature is the boat-shaped (V-shaped) tip. Blades are smooth with a prominent midrib (central vein) and a short, membranous ligule; auricles are absent.
Root System
Moderately shallow fibrous system characterized by strong rhizomes that allow for self-repair and high sod density. Thatch tendency is moderate to high due to rhizomatous growth.
Growing Information
Origin Region
Native to Europe, North Asia, and the mountains of Morocco and Algeria; widely adapted to temperate climates globally.
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense, uniform sod with a moderate rate of spread.
Sunlight & Water Needs
Requires Full Sun (6+ hours) for best performance, though some cultivars tolerate light shade. High watering needs during summer; moderate drought tolerance (enters dormancy to survive dry spells).
Mowing & Maintenance
Ideal height is 2.0 to 3.5 inches. High maintenance level requiring regular fertilization (3-5 lbs N/1000 sq ft/year), core aeration to manage thatch, and frequent mowing.
Special Characteristics
Excellent foot-traffic tolerance due to rhizomatous recovery; susceptible to necrotic ring spot and summer patch; poor salt tolerance; high aesthetic value for home lawns and sports fields.
Ecological Information
Introduced and naturalized in North America. Provides soil stabilization and erosion control; serves as forage for livestock and habitat for small birds; often blended with Perennial Ryegrass or Fine Fescue for genetic diversity.