Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Common or Commercial variety (e.g., 'Kenblue' or mix)
Hardiness Zones
USDA Zones 2-7. Excellent cold tolerance; enters winter dormancy after heavy frost, turning tan/brown if not irrigated or in extreme cold.
About This Grass
A dark-green, medium-textured grass that forms a high-quality, dense turf. It is known for its ability to go dormant during hot, dry summers and recover once conditions improve. Seed heads are open, airy panicles, though rarely seen in maintained lawns.
Blade Characteristics
2-4mm width (medium), boat-shaped tips (rounded and keel-like), smooth texture with two translucent lines (midrib) down the center. Vernation is folded in the bud; ligule is short and membranous; auricles are absent.
Root System
Relatively shallow fibrous root system combined with extensive, thick rhizomes. High thatch tendency due to organic matter buildup from rhizomes; excellent sod-forming capability.
Growing Information
Origin Region
Native to Europe, Northern Asia, and the mountains of Morocco and Algeria; widely adapted to the transition and cool-humid zones of North America.
Growth Habit
Rhizomatous (spreading underground), forming a dense, self-repairing sod.
Sunlight & Water Needs
Full sun preferred (6+ hours); moderate shade tolerance in some cultivars. High water requirement during growth; high drought dormancy survival but requires irrigation to remain green during summer peaks.
Mowing & Maintenance
Ideal height 2.0 to 3.0 inches. Requires frequent mowing and high nitrogen fertilization (2-4 lbs N/1000 sq ft/yr). Requires periodic dethatching and core aeration. Maintenance level: High.
Special Characteristics
Excellent traffic recovery due to rhizomes. Susceptible to summer patch, dollar spot, and necrotic ring spot. High salt sensitivity. Best suited for high-visibility home lawns and athletic fields.
Ecological Information
Introduced/Naturalized in North America. Provides soil stabilization and erosion control. Often mixed with Perennial Ryegrass or Fine Fescues to improve genetic diversity and disease resistance.