Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Common/Mixed Cultivar (e.g., Midnight or Baron type)
Hardiness Zones
USDA Zones 2-7; excellent cold tolerance, poor heat tolerance in the Deep South.
About This Grass
A dark green to blue-green turf grass with a fine to medium texture. It forms a dense, lush carpet when well-maintained. Unmowed, it can reach 12-24 inches with open, airy panicle seed heads.
Blade Characteristics
Blade width 2-4mm; features a distinctive boat-shaped (keeled) tip with two translucent 'skitrack' lines along the midrib. Vernation is folded in the bud; ligule is short and membranous; auricles are absent.
Root System
Moderately deep fibrous root system with extensive rhizomes. Known for forming a thick thatch layer and a tight, durable sod that recovers well from traffic.
Growing Information
Origin Region
Native to Europe, North Asia, and North Africa; widely adapted to temperate climates globally
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense sod
Sunlight & Water Needs
Prefers Full Sun (6+ hours) but tolerates light shade. High water requirement, especially in summer; medium to low drought tolerance, will go dormant during extreme dry heat.
Mowing & Maintenance
Ideal height 2.0-3.5 inches; high maintenance level requiring frequent fertilization (3-5 lbs N per 1000 sq ft/year) and periodic dethatching.
Special Characteristics
Excellent self-repair ability due to rhizomes; high wear tolerance; preferred for high-end residential lawns and athletic fields where irrigation is available.
Ecological Information
Introduced and naturalized in North America; provides soil stabilization and cover for small birds/insects. Often co-exists with weeds like the Hydrocotyle (Pennywort/Dollarweed) visible in the image.