Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Midnight (known for dark green color and dense growth habit)
Hardiness Zones
USDA Zones 3 through 7, highly cold tolerant, goes dormant and turns brown during severe heat or drought conditions
About This Grass
Forms a dense, high-quality turf with a rich medium-to-dark green color. Height ranges from 1.5 to 2.5 inches when maintained, and up to 18-24 inches if unmowed. Features prominent pyramidal seed heads at maturity.
Blade Characteristics
Medium width (3-4mm), flat with distinct parallel veins, boat-shaped tips, folded in the bud (vernation), with a 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 speed; excellent wear recovery due to 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 via underground stems), forming a dense, uniform sod
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily) but has moderate shade tolerance; requires regular watering (1 inch per week) to maintain green color during summer; moderate drought tolerance by entering summer dormancy
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.5 inches; high maintenance level requiring regular fertilization (3-4 lbs N per 1000 sq ft annually), frequent mowing, regular watering, and periodic dethatching/aeration
Special Characteristics
Excellent traffic and wear tolerance due to self-repairing rhizomes, good cold hardiness, moderate disease susceptibility (e.g., leaf spot, dollar spot), poor heavy shade tolerance
Ecological Information
Introduced species in North America, provides standard turf ecosystem benefits, helps prevent soil erosion through dense sod formation, commonly blended with Perennial Ryegrass and Fine Fescue