Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Common blend, often including turf-type cultivars like 'Midnight' or 'Baronie'
Hardiness Zones
Thrives in USDA Hardiness Zones 3 through 7; excellent cold tolerance, moderate heat tolerance, goes dormant in severe winter or extreme summer drought.
About This Grass
Forms a dense, high-quality, medium-textured turf with an attractive rich green to dark blue-green color. Mown height typically ranges from 1.5 to 2.5 inches, while unmowed growth can reach 18 to 24 inches with open, pyramidal panicle seed heads.
Blade Characteristics
Blades are medium width (2-4mm), flat to folded with prominent parallel veins and characteristic boat-shaped (prow-shaped) tips. Vernation is folded in the bud. Ligule is short and membranous, and auricles are absent.
Root System
Moderate to deep fibrous root system combined with extensive underground rhizomes. Forms a very dense sod, medium establishment speed, and moderate thatch-forming tendencies under high fertility.
Growing Information
Origin Region
Europe and northern Asia; widely naturalized and cultivated across North America and temperate regions worldwide
Growth Habit
Rhizomatous, spreading underground via aggressive creeping rootstocks to form a dense, uniform turf
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily) for optimal performance; moderate to high water needs to maintain green color during summer; goes into summer dormancy if moisture is lacking. Prefers well-drained loamy soils with pH between 6.0 and 7.0.
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.0 inches. Requires frequent mowing during peak spring/fall growth. High fertilizer needs (3-5 lbs N per 1000 sq ft per year). Regular aeration and dethatching needed; high maintenance level.
Special Characteristics
Good wear tolerance and excellent self-repairing capabilities due to rhizomes; moderate disease susceptibility (e.g., leaf spot, dollar spot, summer patch); poor shade tolerance compared to fescues; excellent erosion control.
Ecological Information
Introduced species in North America; provides standard urban wildlife habitat and soil stabilization; often blended with Perennial Ryegrass and Creeping Red Fescue for northern lawn mixtures.