Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Standard Northern Mix (cultivar unknown)
Hardiness Zones
USDA Zones 2-7. Excellent cold tolerance; enters winter dormancy and may go dormant in extreme summer heat.
About This Grass
A dense, cool-season turfgrass with a characteristic dark green to blue-green color. It forms a lush carpet and exhibits a moderate growth rate. In the image, it is seen sparsely intermixed with moss, indicating high moisture and potentially low light or acidic soil.
Blade Characteristics
Fine to medium width (2-4mm), V-shaped or flat, featuring a distinct boat-shaped tip. Vernation is folded in the bud. Ligule is short and membranous; auricles are absent.
Root System
Moderately shallow fibrous root system with extensive rhizomes. Forms heavy thatch over time. Slow to moderate establishment from seed but excellent sod-forming capability.
Growing Information
Origin Region
Europe and Northern Asia; well-adapted to Northern US and Canada
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense, sod-forming mat
Sunlight & Water Needs
Full sun preferred (6+ hours), moderate shade tolerance. High water needs; poor drought tolerance compared to fescues (goes dormant during heat/drought).
Mowing & Maintenance
Ideal height 2.0 to 3.5 inches. Requires frequent mowing and regular fertilization (3-5 lbs N per 1000 sq ft annually). High maintenance level.
Special Characteristics
Excellent wear tolerance and recovery due to rhizomes. Susceptible to leaf spot, melting out, and necrotic ring spot. High aesthetic value for home lawns.
Ecological Information
Introduced and naturalized in North America. Provides soil stabilization but can be outcompeted by moss (as seen in image) in wet, shaded, or compacted conditions.