Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae
Grass Category
Lawn/Turf Grass, Sports Turf
Variety / Cultivar
'Midnight' or similar dark green elite cultivar
Hardiness Zones
USDA Hardiness Zones 3 to 7, excellent cold tolerance, moderate heat tolerance, goes dormant in extreme summer heat.
About This Grass
Forms a dense, uniform, fine-to-medium textured turf with rich dark green to blue-green color. Reaches up to 18-24 inches if unmoved, but typically maintained at 1.5-2.5 inches. Produces characteristic pyramidal panicle seed heads at maturity.
Blade Characteristics
Blades are medium-width (3-4mm), flat with distinct parallel veins, and feature classic boat-shaped tips. Vernation is folded in the bud. Ligule is short and membranous, auricles are absent.
Root System
Moderately deep fibrous root system combined with extensive rhizomes. Forms a very dense sod, moderate thatch tendency, slow to germinate and establish, but exhibits excellent wear recovery through its spreading rhizomes.
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 rhizomes to form a dense, uniform turf mat.
Sunlight & Water Needs
Requires full sun (at least 6 hours of direct sunlight), moderate to high watering needs during dry spells, goes into summer dormancy if unwatered, prefers well-drained fertile soils with a pH of 6.0-7.0.
Mowing & Maintenance
Maintain at 2.0 to 3.0 inches. Medium to high maintenance level requiring regular fertilization (3-4 lbs N per 1000 sq ft per year), periodic aeration, and dethatching.
Special Characteristics
High traffic and wear tolerance due to aggressive self-repairing rhizomes, moderate disease susceptibility (e.g., leaf spot, dollar spot), excellent winter color retention in milder cool regions, forms exceptionally dense turf that crowds out weeds.
Ecological Information
Introduced to North America by European settlers. Provides standard lawn ecosystem services, excellent soil stabilization and erosion control, and is frequently blended with perennial ryegrass and fine fescues.