Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Most likely a common blend or older cultivar like Kenblue; modern elite cultivars like 'Midnight' are typically darker and denser than seen here.
Hardiness Zones
USDA Zones 2-7; excellent cold tolerance but struggles in the humid South (Zone 8+); goes dormant in winter or extreme summer heat.
About This Grass
A dense, low-growing grass with a vibrant green to blue-green color. It forms a uniform carpet-like surface when well-maintained. If left unmowed, it reaches 12-24 inches and produces open, pyramid-shaped panicle seed heads.
Blade Characteristics
Fine to medium width (2-4mm); smooth blades with a distinct V-shape; most diagnostic feature is the boat-shaped (cupped) leaf tip; vernation is folded in the bud; ligule is short and membranous; no auricles.
Root System
Moderately shallow fibrous root system with extensive horizontal rhizomes; forms a significant thatch layer; slower to establish from seed than ryegrass but forms a more stable sod.
Growing Information
Origin Region
Native to Europe, North Asia, and the mountains of Morocco and Algeria; best adapted to cool, humid climates.
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense, thick sod; slow to establish but excellent at self-repairing.
Sunlight & Water Needs
Prefers full sun (minimum 6 hours); moderate shade tolerance; requires consistent moisture and is not highly drought-resistant, though it may go dormant (brown) to survive extreme heat.
Mowing & Maintenance
Ideal height 2.0 to 3.5 inches; requires frequent mowing during peak spring and fall growth; fertilization needs are medium-high (2-4 lbs N per 1000 sq ft/year); needs periodic dethatching.
Special Characteristics
Excellent wear tolerance and recovery due to rhizomes; good ability to crowd out weeds; prone to dollar spot, necrotic ring spot, and summer patch in high humidity.
Ecological Information
Introduced/Naturalized (non-native to North America); provides cover for small mammals; highly effective for erosion control on slopes due to sod-forming nature; commonly blended with Perennial Ryegrass and Fine Fescue.