Kentucky Bluegrass
Poa pratensis · Cool-season (C3), Perennial
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf, Golf Course Grass (fairways/tees)
Variety / Cultivar
Representative of high-density cultivars like 'Midnight' or 'Mazama'
Hardiness Zones
USDA Hardiness Zones 2-7; excellent cold tolerance; poor heat tolerance in deep South (Zone 8+); goes dormant in winter/extreme summer heat.
About This Grass
A dark green, high-density turf grass known for its lush appearance. When unmowed, it grows 12-24 inches tall with open, pyramidal panicle seed heads. In turf, it exhibits a uniform, fine-to-medium texture and exceptional ability to recover from traffic via rhizome expansion.
Blade Characteristics
Width: 2-4mm (medium); Shape: V-shaped or flat; Tip: Distinctive boat-shaped (keeled) tip; Color: Dark emerald green to blue-green; Vernation: Folded in the bud; Ligule: Short, membranous, and truncate; Auricles: Absent; Collar: Narrow to medium, glabrous.
Root System
Moderately deep fibrous root system with extensive rhizomes; highly sod-forming; moderate thatch producer; slower establishment from seed compared to ryegrass but excellent long-term stability and wear recovery.
Growing Information
Origin Region
Native to Europe, Northern Asia, and North Africa; widely naturalized in North America and temperate climates globally.
Growth Habit
Rhizomatous (spreading via underground stems), forms a dense, sod-forming mat.
Sunlight & Water Needs
Sunlight: Full sun (prefers 6+ hours) but can tolerate light shade; Water: High water needs, requires approx. 1 inch per week; Drought: Moderate (enters dormancy quickly during heat/drought to survive); Soil: Prefers well-drained, fertile soils with pH 6.0-7.0.
Mowing & Maintenance
Mowing Height: 1.5-3 inches; Frequency: Weekly; Fertilization: 2-4 lbs Nitrogen/1,000 sq ft annually; Maintenance: High (requires regular fertilization, irrigation, and occasional core aeration/dethatching).
Special Characteristics
High wear tolerance for sports, excellent recuperative potential, superior winter hardiness, provides the 'classic' lawn look, moderate resistance to most diseases though susceptible to Necrotic Ring Spot and Summer Patch in high heat.
Ecological Information
Introduced but widely naturalized; provides cover and forage for small mammals and birds; excellent for soil erosion control due to dense sod formation; often blended with Perennial Ryegrass or Fine Fescue to improve overall turf resilience.