Kentucky Bluegrass (manifesting dormancy)
Poa pratensis · Cool-season, Perennial, C3
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf, and Erosion Control
Variety / Cultivar
Common or 'Commercial' type (likely a standard sod-grade or pasture-type mix)
Hardiness Zones
USDA Zones 2-7; excellent cold tolerance; poor heat tolerance (enters summer dormancy as shown in the image).
About This Grass
A fine to medium-textured grass known for its dark green color when hydrated. In the image, it is in a state of summer dormancy, appearing straw-colored and brown due to heat/drought stress. When healthy, it grows 12-24 inches unmowed with panicle-shaped seed heads.
Blade Characteristics
Fine to medium width (2-4mm); V-shaped or flat; boat-shaped leaf tips (distinctive); folded vernation; short membranous ligule; no auricles.
Root System
Relatively shallow fibrous root system compared to tall fescue, but widespread rhizomes allow for excellent sod density and self-repair capabilities.
Growing Information
Origin Region
Europe, Northern Asia, and Morocco; naturalized throughout North America
Growth Habit
Rhizomatous (underground spreading) forming a dense, thick sod; slow to moderate spread speed.
Sunlight & Water Needs
Full sun preferred; poor shade tolerance (needs 6+ hours); high water requirement to stay green; becomes dormant (brown) during extended drought to protect the crown.
Mowing & Maintenance
Ideal height 2.5-3.5 inches; high maintenance; requires 2-4 lbs Nitrogen per 1000 sq ft; prone to thatch buildup requiring periodic dethatching.
Special Characteristics
Excellent traffic/wear tolerance and recovery; high aesthetic value; highly susceptible to Necrotic Ring Spot and Summer Patch in high heat.
Ecological Information
Introduced and naturalized; provide nesting cover for small birds when unmowed; excellent soil stabilizer for slopes due to rhizomatous matting.