Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
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 to 7. Excellent cold tolerance, goes semi-dormant and turns brown during extreme heat or prolonged drought unless irrigated.
About This Grass
Forms a dense, high-quality turf with a rich dark blue-green color. Mown height typically ranges from 1.5 to 2.5 inches, while unmowed growth can reach 18 to 24 inches. Features an erect growth habit and distinctive open, pyramidal panicle seed heads at maturity.
Blade Characteristics
Medium-fine blade width (2-4mm), flat to folded shape with characteristic boat-shaped tips. Color is dark blue-green. Vernation is folded in the bud with prominent parallel veins creating a railroad-track appearance. Features a short membranous ligule and lacks auricles.
Root System
Moderate depth fibrous root system combined with vigorous rhizomes. Forms a very dense sod that has moderate to high thatch-forming tendencies. Slow to moderate establishment speed from seed, but excellent self-repairing wear recovery.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America and temperate regions worldwide, performing best in northern climates.
Growth Habit
Rhizomatous, spreading extensively via underground stems to form a dense, uniform turf mat.
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily), moderate to high water needs to maintain green color during summer, and moderate drought tolerance (enters dormancy during severe drought). 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. Requires frequent mowing during peak spring/fall growth. High fertilizer requirement (3-5 lbs N per 1000 sq ft per year). Moderate to high maintenance level involving regular aeration and occasional dethatching.
Special Characteristics
Good wear tolerance and excellent recuperative ability due to rhizomes. Fair to moderate shade tolerance. Susceptible to certain diseases like leaf spot, dollar spot, and summer patch under stress. Excellent weed suppression due to dense growth.
Ecological Information
Introduced species in North America. Provides moderate wildlife value for grazing herbivores and ground-nesting birds. Excellent for soil stabilization and preventing erosion due to dense root and rhizome matrix. Frequently blended with perennial ryegrass and fine fescues.