Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae
Grass Category
Lawn/Turf Grass, Sports Turf
Variety / Cultivar
Midnight (known for dark blue-green color and high density)
Hardiness Zones
USDA Hardiness Zones 3-7, excellent cold tolerance, moderate heat tolerance, goes dormant in extreme summer heat
About This Grass
Forms a dense, high-quality turf with a fine to medium texture and rich dark green to blue-green color. Mowed height typically maintained at 2-3 inches, while unmowed height can reach 18-24 inches with pyramidal seed heads.
Blade Characteristics
Medium-fine width (2-4mm), flat to V-shaped with distinct parallel veins, distinct boat-shaped tip, folded in the bud (vernation), short membranous ligule, and absent auricles
Root System
Moderately deep fibrous root system with extensive underground rhizomes; moderate to high thatch-forming tendency; slow to moderate establishment from seed; excellent long-term wear recovery via spreading rhizomes
Growing Information
Origin Region
Europe, Northern Asia, and parts of North America; widely cultivated in cool-temperate regions worldwide
Growth Habit
Aggressively rhizomatous, forming a dense, uniform turf mat and sod
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily) for best performance, moderate to high water needs during dry spells, goes into summer dormancy during severe drought, prefers well-drained loamy soils with pH 6.0-7.0
Mowing & Maintenance
Mow at 2.0 to 3.0 inches weekly during active growth, high fertilization needs (3-5 lbs N per 1000 sq ft annually), regular dethatching and core aeration needed, high maintenance level
Special Characteristics
Good wear tolerance and self-repairing capability due to rhizomes, moderate disease susceptibility (summer patch, dollar spot), poor shade tolerance, excellent cold hardiness and winter color retention in milder zones
Ecological Information
Introduced to North America by European settlers, provides good erosion control and dense soil stabilization, highly valued for residential and commercial turf landscapes, frequently blended with perennial ryegrass and fescues