Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 carbon fixation pathway
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf
Variety / Cultivar
Standard/Common (likely part of a mixed lawn seed blend containing older cultivars like 'Kenblue' or 'Baron')
Hardiness Zones
USDA Zones 2-7; excellent cold tolerance and winter hardiness; enters summer dormancy in heat and winter dormancy in freezing temperatures.
About This Grass
A dense, low-growing grass with a soft texture. It displays a characteristic deep blue-green color when healthy, but turns dormant and straw-colored (as seen in the photo) during periods of high heat or water stress. Unmowed height reaches 12-24 inches with open, pyramidal panicle seed heads.
Blade Characteristics
Blade width is fine to medium (2-4mm). The most distinctive feature is the boat-shaped (keeled) leaf tip. Vernation is folded in the bud; ligule is short and membranous; auricles are absent. Surface is smooth with a distinct mid-rib.
Root System
Moderately shallow fibrous root system supported by a dense network of rhizomes. High thatch-forming tendency; moderate establishment speed from seed, but excellent sod-forming capability and wear recovery.
Growing Information
Origin Region
Native to Europe, Asia, and North Africa; widely naturalized and the primary lawn grass across Northern USA and Canada
Growth Habit
Rhizomatous; spreads via underground creeping stems to form a thick, sod-forming mat that can self-repair bare spots
Sunlight & Water Needs
Full sun preferred (minimum 6 hours); poor shade tolerance compared to fescues. Requires high water input (1-1.5 inches per week) to remain green. High drought dormancy (survives by turning brown) but low drought resistance.
Mowing & Maintenance
Recommended height: 2.5-3.5 inches. High maintenance level; requires 3-5 lbs of Nitrogen per 1000 sq ft annually. Needs regular dethatching and aeration due to rhizomatous growth.
Special Characteristics
Excellent self-healing ability due to rhizomes; good wear tolerance for foot traffic; prone to Summer Patch, Dollar Spot, and Necrotic Ring Spot; low salt tolerance.
Ecological Information
Introduced/Naturalized in North America. Provides significant erosion control through dense sod. Serves as a host for various Lepidoptera (butterfly/moth) larvae. Often blended with Perennial Ryegrass and Fine Fescue for diverse lawn ecosystems.