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 (Fairways/Tees)
Variety / Cultivar
Midnight (Representative of Aggressive/Compact type)
Hardiness Zones
USDA Hardiness Zones 2-7; excellent cold tolerance; poor heat tolerance in deep south; goes dormant and turns brown in extreme cold or heat.
About This Grass
A dark green, high-density turf grass that forms a smooth, uniform surface. Under managed conditions, it maintains a rich color and fine-to-medium texture. When unmowed, it can reach 12-24 inches with open, airy panicle seed heads.
Blade Characteristics
Fine to medium width (2-4mm); V-shaped or flat; distinctive boat-shaped (keeled) tip; dark green color; folded vernation; very short membranous ligule; no auricles.
Root System
Moderately deep fibrous root system complemented by extensive rhizomes. High thatch potential due to rhizomatous density; good recovery speed from wear via rhizome self-repair.
Growing Information
Origin Region
Native to Europe, Northern Asia, and the mountains of Morocco and Algeria. Well-adapted to temperate climates globally.
Growth Habit
Rhizomatous; forms a thick, dense sod by spreading via underground stems (rhizomes).
Sunlight & Water Needs
Prefers Full Sun (minimum 6 hours); moderate shade tolerance in specific cultivars; high water requirements (1-1.5 inches per week); enters summer dormancy during severe drought.
Mowing & Maintenance
Ideal height 2.0 to 3.5 inches; frequent mowing required during spring/fall peaks; 2-4 lbs N per 1,000 sq ft annually; requires periodic dethatching and aeration; high maintenance level.
Special Characteristics
Excellent wear tolerance and recovery; high aesthetic quality; susceptible to necrotic ring spot and summer patch; poor salt tolerance; excellent density for weed suppression.
Ecological Information
Introduced/Naturalized in North America; provides cover for small mammals; stabilizes soil effectively through sod formation; often mixed with Perennial Ryegrass or Fine Fescue for biodiversity.