Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Generic / Common Kentucky Bluegrass (often mixed with other cultivars like 'Midnight' or 'Mazama' in residential lawns)
Hardiness Zones
USDA Hardiness Zones 2-7; thrives in cool, humid climates and transition zones with high elevation.
About This Grass
A dark-green, medium-textured turfgrass that forms a thick, carpet-like lawn. It remains dormant during hot, dry summers and extremely cold winters, regaining its lush green color in spring and fall. Seed heads are open, pyramidal panicles.
Blade Characteristics
Blades are medium width (2-4mm), folded in the bud (folded vernation), with a distinct 'v-shaped' cross-section and a unique boat-shaped tip. Color is typically deep emerald to blue-green. Ligules are short and membranous; auricles are absent.
Root System
Produces a shallow to medium-depth fibrous root system with extensive rhizomes. It has a high thatch-forming tendency but provides excellent sod strength and recovery capacity from wear.
Growing Information
Origin Region
Native to Europe, North Asia, and the mountains of Algeria and Morocco; widely adapted to temperate regions worldwide
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense, uniform sod
Sunlight & Water Needs
Prefers Full Sun (6+ hours) but can tolerate light shade. Requires moderate to high watering; has poor drought resistance but excellent drought dormancy/survival mechanisms.
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.5 inches. High maintenance level: requires regular fertilization (3-5 lbs N per 1,000 sq ft/year) and periodic dethatching/core aeration.
Special Characteristics
Excellent traffic tolerance and self-repair capabilities due to rhizomes. Susceptible to leaf spot, melting out, and necrotic ring spot. Highly valued for its soft texture and aesthetic beauty.
Ecological Information
Introduced and naturalized in North America. Provides erosion control via dense sod. Supports various insect species and provides nesting cover for ground-dwelling birds in un-mown states.