Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae
Grass Category
Lawn/Turf Grass, Sports Turf
Variety / Cultivar
Common blend or standard turf-type cultivars; highly variable in residential lawns
Hardiness Zones
Thrives in USDA Hardiness Zones 3 through 7; excellent cold tolerance, moderate heat tolerance, often combined with tall fescue in transition zones
About This Grass
Forms a dense, medium-fine textured turf with rich dark green to blue-green coloration; shows patches of dormancy and brown thatch/dry grass under environmental stress; height typically maintained at 1.5 to 2.5 inches, can grow up to 12-24 inches if unmowed with open, pyramidal panicle seed heads
Blade Characteristics
Medium-fine blades (2-4mm wide) with distinctive boat-shaped tips, folded in the bud (vernation), prominent parallel veins creating a railroad-track appearance, smooth texture, prominent membranous ligule, and lacking auricles
Root System
Moderately deep fibrous root system combined with an extensive network of underground rhizomes; moderate establishment speed, forms a dense sod with a tendency to build up thatch over time
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America and temperate regions worldwide
Growth Habit
Aggressively rhizomatous, spreading underground via slender rhizomes to form a dense, uniform sod
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily) for optimal growth; moderate to high water needs to maintain green color during summer; goes dormant during severe drought and greens up quickly upon receiving moisture; prefers well-drained fertile soils with a pH of 6.0 to 7.0
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.0 inches; regular mowing frequency during active spring and fall growth periods; medium to high maintenance level requiring 2-4 lbs N per 1000 sq ft annually, periodic dethatching, and aeration
Special Characteristics
Excellent traffic and wear tolerance due to aggressive rhizomatous self-repair; moderate shade tolerance (performs poorly in dense shade); prone to certain diseases like dollar spot and leaf spot under high humidity and improper fertilization; excellent winter color retention compared to warm-season grasses
Ecological Information
Introduced species in North America; provides standard urban wildlife habitat and soil stabilization; frequently blended with Perennial Ryegrass and Fine Fescues to form resilient residential and commercial turf mixes