Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 carbon fixation
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf, Golf Course Grass
Variety / Cultivar
Generic / Common Kentucky Bluegrass (Specific cultivar requires DNA or seed certification; exhibits standard high-density upright growth)
Hardiness Zones
USDA Zones 2-7; excellent cold tolerance; poor heat tolerance in the deep South; goes dormant in both extreme winter cold and summer heat/drought.
About This Grass
A fine to medium-textured grass known for its dark green to blue-green color. It grows in a soft, dense carpet-like manner. If left unmowed, it reaches heights of 12-24 inches with open, pyramid-shaped panicle seed heads.
Blade Characteristics
Width: 2-4mm (medium); Shape: Flat or slightly V-shaped; Tip: Distinctive boat-shaped (keeled) leaf tip; Color: Deep green to bluish-green; Vernation: Folded in the bud; Ligule: Short, membranous, and truncated; Auricles: Absent; Collar: Narrow and continuous.
Root System
Moderately deep fibrous root system complemented by extensive rhizomes. Forms heavy thatch; excellent establishment speed from sod, slower from seed; excellent sod-knitting ability for wear recovery.
Growing Information
Origin Region
Europe, Northern Asia, and North Africa; now dominant throughout the Northern US and Southern Canada (Cool-Humid regions)
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense, sod-forming mat; moderate rate of spread
Sunlight & Water Needs
Requires Full Sun (6+ hours) for best performance; moderate to high water needs; enters dormancy during severe drought to survive; prefers well-drained fertile soil with pH 6.0-7.2.
Mowing & Maintenance
Ideal height: 2.0 to 3.5 inches. High maintenance level: requires consistent fertilization (3-5 lbs N per 1000 sq ft/year), regular irrigation, and occasional core aeration to manage thatch.
Special Characteristics
Exceptional wear tolerance due to rhizomatous self-repair; high aesthetic value; relatively high disease susceptibility (Leaf Spot, Melting Out, Summer Patch) but recovers quickly; low shade tolerance.
Ecological Information
Introduced/Naturalized (non-native to North America); provides cover for small mammals; excellent for erosion control on slopes due to rhizomes; often blended with Perennial Ryegrass or Fine Fescue for ecological resilience.