Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf
Variety / Cultivar
Midnight (known for dark blue-green color, excellent density, and disease resistance)
Hardiness Zones
Thrives in USDA Hardiness Zones 3 through 7. Excellent cold tolerance, surviving sub-zero winter temperatures through dormancy. Can struggle in extreme summer heat unless irrigated.
About This Grass
Forms a dense, fine-to-medium textured turf with an attractive rich green to dark blue-green color. Unmowed height reaches 18 to 24 inches with open panicle seed heads, but typically maintained at 1.5 to 3 inches. Shows good density but can accumulate thatch over time.
Blade Characteristics
Blades are medium width (2-4mm), flat to folded with distinct parallel veins and a prominent midvein. The tips are characteristically boat-shaped (prow-tipped). Vernation is folded in the bud. Ligule is short and membranous; auricles are absent.
Root System
Moderate root depth with extensive, strong rhizomes that create a very dense sod. Establishes slowly from seed compared to ryegrass, but forms an interconnected root network providing excellent long-term wear recovery and moderate drought dormancy.
Growing Information
Origin Region
Native to Europe, northern Asia, and parts of the mountains of North America; widely cultivated throughout temperate regions worldwide, performing best in northern climates.
Growth Habit
Aggressively rhizomatous, spreading via underground stems to form a dense, uniform, and tightly knit turf sod.
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily) for optimal performance; moderate shade tolerance. High watering needs during dry spells to maintain green color, though it enters summer dormancy under severe drought. Prefers well-drained, fertile soils with a pH of 6.0-7.0.
Mowing & Maintenance
Ideal mowing height ranges from 2.0 to 3.0 inches. Requires regular mowing during active spring and fall growth periods. Medium-to-high maintenance level, needing 3-4 lbs of nitrogen per 1000 sq ft annually, along with periodic dethatching and core aeration.
Special Characteristics
Good traffic and wear tolerance due to aggressive rhizomatous recovery. Moderate disease resistance (though susceptible to dollar spot, rust, and leaf spot depending on the cultivar). Excellent winter color retention in milder zones, and forms a dense barrier against weeds.
Ecological Information
Introduced species in North America widely used for turfgrass and erosion control. Provides turf cover and soil stabilization, filters runoff water, and is frequently blended with Perennial Ryegrass and Fine Fescue for resilient lawn ecosystems.