Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Common lawn-type Kentucky Bluegrass (likely a blend including cultivars like 'Midnight' or 'Kenblue')
Hardiness Zones
USDA Zones 2-7. Excellent cold tolerance; struggles in the humid South (Zone 8+).
About This Grass
A medium-textured, cool-season grass known for its rich emerald to blue-green color. It forms a dense turf and enters dormancy during extreme heat or drought, turning tan/brown as seen in the patchy areas of the provided image.
Blade Characteristics
Fine to medium width (2-4mm), V-shaped or flat, featuring a distinct boat-shaped tip. Vernation is folded in the bud; ligule is short and membranous; auricles are absent.
Root System
Relatively shallow fibrous root system with extensive rhizomes. Forms significant thatch; slow to establish from seed but creates a very durable sod once mature.
Growing Information
Origin Region
Native to Europe, North Asia, and parts of North Africa; widely adapted throughout Northern United States and Canada
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense, self-repairing sod
Sunlight & Water Needs
Full sun preferred (6+ hours); moderate shade tolerance. High water requirement, needing 1-1.5 inches per week. Exhibits good drought dormancy but poor drought avoidance.
Mowing & Maintenance
Ideal height 2.5 to 3.5 inches. High maintenance: requires regular fertilization (3-5 lbs N/1000 sq ft/year) and periodic dethatching or core aeration.
Special Characteristics
Excellent wear tolerance and recovery due to rhizomes. Susceptible to Necrotic Ring Spot and Summer Patch (which may be causing the circular browning seen in the image).
Ecological Information
Introduced/Naturalized in North America. Provides forage for wildlife and stabilization for soil. Often mixed with Perennial Ryegrass or Fine Fescue for genetic diversity.