Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf, Golf Course Fairways
Variety / Cultivar
Common or Commercial variety (e.g., 'Merit' or 'Kenblue'); exhibits standard medium-green color and spreading habit
Hardiness Zones
USDA Hardiness Zones 2-7; excellent cold tolerance, poor heat tolerance in the Deep South; goes dormant in winter and extreme summer heat.
About This Grass
A dense, cool-season turfgrass known for its smooth, durable mat and medium-green color. It reaches 12-24 inches when unmowed, producing pyramidal panicle seed heads. It enters dormancy in extreme heat or drought.
Blade Characteristics
Blade width is medium (2-4mm). The most defining feature is the boat-shaped (V-shaped) tip. Blades are smooth, folded in the bud (folded vernation), with two distinct 'track-mark' lines on either side of the midrib. Ligule is short and membranous; auricles are absent.
Root System
Moderately shallow fibrous roots combined with extensive rhizomes. Its rhizomatous nature allows for high thatch tendency but excellent recuperative potential and sod strength.
Growing Information
Origin Region
Native to Europe, North Asia, and Northern Africa; widely naturalized in North America and cool-temperate climates worldwide
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense, self-repairing sod mat
Sunlight & Water Needs
Prefers full sun (minimum 6 hours) but can tolerate light shade. Requires moderate to high water; drought-tolerant via dormancy but loses color without regular irrigation. Prefers pH 6.0-7.0.
Mowing & Maintenance
Mowing height 2.0 to 3.5 inches. High maintenance level; requires 2-4 lbs of Nitrogen per 1000 sq ft annually. Needs periodic aeration and dethatching due to rhizome buildup.
Special Characteristics
High wear tolerance and excellent ability to crowd out weeds through rhizomatous spread. Susceptible to leaf spot, melting out, and necrotic ring spot diseases.
Ecological Information
Introduced and naturalized in North America. Provides significant soil stabilization and erosion control. Used often in blends with Perennial Ryegrass or Fine Fescues to increase biodiversity and disease resistance.