Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Common or unknown cultivar (variety appears to be a standard turf-type mixture)
Hardiness Zones
USDA Zones 2-7; excellent cold hardiness but poor heat tolerance in the Deep South. Goes dormant (turns brown) during extreme cold or high summer heat without irrigation.
About This Grass
Medium-textured turf grass with a prominent emerald to dark green color. It forms a dense carpet-like lawn. When left unmowed, it reaches 12-24 inches with open, pyramidal panicle seed heads. Displays a distinct V-shape at the blade base.
Blade Characteristics
Blade width is medium (2-4mm). The most identifying feature is the boat-shaped (keeled) blade tip. Vernation is folded in the bud; leaf surface is smooth with a distinct mid-rib (twin mid-veins). Ligule is short and membranous; auricles are absent.
Root System
Moderately shallow fibrous root system supported by vigorous rhizomes. High thatch-forming tendency. Excellent sod-forming capacity but slower establishment from seed than ryegrass.
Growing Information
Origin Region
Native to Europe, Northern Asia, and the mountains of Morocco and Algeria; widely naturalized in Northern US and Canada.
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense, self-repairing sod.
Sunlight & Water Needs
Full sun preferred (requires 6+ hours); moderate shade tolerance. High water requirements; enters summer dormancy during extended drought to protect crown. Prefers well-drained soil with pH 6.0-7.0.
Mowing & Maintenance
Ideal height: 2.5 to 3.5 inches. High maintenance level. Requires 2-4 lbs of Nitrogen per 1000 sq ft annually. Needs regular dethatching due to rhizome production and core aeration every 1-2 years.
Special Characteristics
Excellent wear tolerance and recovery due to rhizomes. Susceptible to Leaf Spot, Dollar Spot, and Summer Patch. Moderate salt tolerance. Highly prized for its soft feel and uniform appearance in home lawns.
Ecological Information
Introduced and naturalized in North America. Provides habitat for small invertebrates; seeds are food for songbirds. Effective for soil stabilization in temperate climates. Often mixed with Perennial Ryegrass and Fine Fescue for diversity.