Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass, Pasture, and Native Prairie Grass
Variety / Cultivar
Native/Common variety (non-specific)
Hardiness Zones
USDA Hardiness Zones 2 to 7. Excellent cold tolerance; poor heat tolerance in deep South (Zone 8+). Goes dormant in winter/extreme heat.
About This Grass
A medium-textured grass with a distinctive dark green to blue-green color. It forms a dense turf when maintained. If unmowed, it reaches 12-24 inches with panicle-type seed heads that are open and pyramid-shaped.
Blade Characteristics
Fine to medium width (2-4mm), V-shaped or flat, featuring a unique boat-shaped tip. Color is typically deep blue-green. Vernation is folded in the bud; ligule is short and membranous; auricles are absent.
Root System
Relatively shallow but dense fibrous root system supported by horizontal rhizomes. High thatch tendency; moderate establishment speed from seed; creates excellent sod strength.
Growing Information
Origin Region
Native to Europe, North Asia, and the mountains of Morocco and Algeria; widely naturalized in North America and temperate climates.
Growth Habit
Rhizomatous (spreading via underground runners), producing a dense, sod-forming mat with a slow to moderate spread rate.
Sunlight & Water Needs
Prefers full sun (6+ hours) but has moderate shade tolerance. High water requirements; enters summer dormancy during severe drought to protect the crown.
Mowing & Maintenance
Ideal height 2.0 to 3.5 inches. Requires frequent mowing during peak spring/fall growth. Medium to high maintenance; fertilization needs 2-4 lbs N per 1000 sq ft annually.
Special Characteristics
Excellent wear recovery due to rhizomes; susceptible to leaf spot, melting out, and necrotic ring spot; high palatability for livestock; widely used for sports fields and premium home lawns.
Ecological Information
Introduced/Naturalized status in North America; provides cover for small mammals; stabilizing root system prevents erosion; often blended with Perennial Ryegrass or Tall Fescue for diversity.