Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
General species (commonly cultivars like 'Midnight' or 'Compact' types)
Hardiness Zones
USDA Hardiness Zones 3 to 7. Excellent cold tolerance, but struggles with intense heat and humidity in the deep southern US without high management.
About This Grass
Forms a dense, fine-to-medium textured turf with an attractive rich green to blue-green color. Grows 1.5 to 2.5 feet tall if left unmowed. In the image, patches are showing severe heat stress, drought dormancy, or disease damage alongside actively growing green tillers.
Blade Characteristics
Medium fineness (2-4mm wide), flat or folded with distinct parallel veins and characteristic boat-shaped (keeled) tips. Vernation is folded in the bud. Ligule is short and membranous; auricles are absent.
Root System
Moderately deep fibrous root system with extensive underground rhizomes that aid in rapid recovery from wear and damage. Forms a very dense sod, can develop moderate thatch under high management.
Growing Information
Origin Region
Europe, Northern Asia, and parts of the mountains of North America; widely cultivated throughout the northern United States and Canada.
Growth Habit
Aggressively rhizomatous, forming a dense, uniform turf and strong sod.
Sunlight & Water Needs
Requires full sun (minimum 6 hours of direct sunlight daily) and consistent moisture. Moderate-to-high watering needs; goes into summer dormancy (turning brown as seen in parts of the photo) during extended drought.
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.0 inches. Requires frequent mowing during active spring and fall growth. Medium-high maintenance level, requiring regular fertilization, aeration, and occasional dethatching.
Special Characteristics
High traffic and wear tolerance due to aggressive rhizomatous spreading and self-repair capabilities. Susceptible to certain diseases like dollar spot, summer patch, and leaf spot under stress.
Ecological Information
Introduced species in North America widely used for lawns, parks, and sports fields. Provides soil stabilization and a dense canopy that effectively prevents erosion and suppresses weeds when healthy.