Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 pathway; typical of the transition and northern zones.
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass; Residential mixed lawn with clover and broadleaf weeds.
Variety / Cultivar
Common/Mixed Cultivar (Appears to be a standard non-dwarf mix or naturalized variety)
Hardiness Zones
USDA Zones 2-7; excellent cold tolerance; poor performance in high heat/humidity of the deep South (Zones 8+).
About This Grass
A dark to medium green perennial grass that forms a soft, dense turf. It is currently mixed with Trifolium repens (White Clover). Left unmowed, it reaches 6-12 inches; maintained, it produces a lush, carpeting effect with fine to medium texture.
Blade Characteristics
Fine to medium width (2-4mm); iconic boat-shaped (V-shaped) leaf tips; folded vernation in the bud; two distinct 'mid-rib' parallel lines along the center of the leaf; ligule is short and membranous; auricles are absent.
Root System
Moderately shallow fibrous root system combined with strong rhizomes; forms a thick, durable sod but requires more water than fescues due to shallower roots; slow establishment compared to ryegrass.
Growing Information
Origin Region
Native to Europe, Northern Asia, and parts of Africa; widely naturalized across North America.
Growth Habit
Rhizomatous; spreads via underground creeping stems to form a dense, sod-forming mat.
Sunlight & Water Needs
Full Sun preferred (6+ hours); moderate shade tolerance; requires consistent moisture through rainfall or irrigation; goes dormant (brown) during prolonged summer drought to protect crown.
Mowing & Maintenance
Ideal height 2.5 to 3.5 inches; high maintenance; requires high nitrogen fertilization (2-4 lbs N/1000 sq ft/year); benefits from annual aeration to manage thatch buildup.
Special Characteristics
Excellent self-repair ability due to rhizomes; high foot traffic tolerance; superior winter color compared to warm-season grasses; prone to necrotic ring spot and summer patch in high heat.
Ecological Information
Introduced species in North America; provides soil stabilization; frequently mixed with Perennial Ryegrass or Fine Fescue to improve disease resistance; clover (visible in image) acts as a companion providing natural nitrogen fixation.