Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Common blend or unspecified turf-type cultivars
Hardiness Zones
USDA Hardiness Zones 3 through 7, highly cold tolerant, goes into winter dormancy in colder regions, struggles in extreme summer heat unless irrigated.
About This Grass
Forms a dense, fine-to-medium textured turf with a rich green to blue-green color. Mown lawn height typically ranges from 2 to 3 inches, while unmowed growth can reach 18 to 24 inches with open, pyramidal panicle seed heads.
Blade Characteristics
Blades are medium-fine (2-4mm wide), flat to folded with distinct parallel veins, featuring characteristic boat-shaped tips. Vernation is folded in the bud with a short, membranous ligule and absent auricles.
Root System
Fibrous root system with extensive underground rhizomes. Moderate rooting depth, forms a very dense sod with a tendency to build up thatch if over-fertilized; slow to establish from seed.
Growing Information
Origin Region
Europe and Northern Asia, widely naturalized and cultivated across North America and temperate regions worldwide
Growth Habit
Aggressively rhizomatous, forming a dense, uniform sod and spreading via underground stems
Sunlight & Water Needs
Requires full sun to partial shade (minimum 4 to 6 hours of direct sunlight). Moderate to high watering needs for optimal appearance, enters summer dormancy during severe drought; prefers well-drained loamy soils with a pH of 6.0 to 7.0.
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.0 inches. Requires frequent mowing during peak spring/fall growth. High maintenance level requiring regular fertilization (2-4 lbs N/1000 sq ft/year), periodic dethatching, and aeration.
Special Characteristics
Excellent traffic and wear tolerance with strong recuperative ability due to rhizomes. Susceptible to certain diseases like dollar spot and leaf spot. Good shade tolerance compared to warm-season grasses but inferior to fine fescues.
Ecological Information
Introduced species in North America. Provides good soil stabilization and erosion control due to dense root and rhizome network. Commonly blended with perennial ryegrass and fine fescues for home lawns and sports fields.