Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf, Golf Course Grass
Variety / Cultivar
Midnight (known for dark blue-green color and high density)
Hardiness Zones
USDA Hardiness Zones 3 through 7; thrives in cool temperate climates with cold winters and moderate summers.
About This Grass
Forms a dense, high-quality turf with a fine to medium texture. Rich dark green to blue-green color. Typical maintained height is 1.5 to 2.5 inches, while unmowed it can reach 18 to 24 inches with open, pyramidal panicle seed heads.
Blade Characteristics
Blades are medium-width (2-4mm), flat to folded with distinct parallel veins and characteristic boat-shaped (prow-shaped) tips. Vernation is folded in the bud. Ligule is short and membranous, auricles are absent, and the collar region is narrow and continuous.
Root System
Moderately deep fibrous root system combined with aggressive rhizomes. Forms a very dense sod, has a moderate to high tendency to produce thatch, and establishes relatively slowly from seed.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America and cool temperate regions worldwide
Growth Habit
Rhizomatous, spreading extensively via underground stems to form a dense, uniform turf mat
Sunlight & Water Needs
Performs best in full sun (minimum 6-8 hours of direct sunlight). Requires regular moisture for optimal appearance and growth; moderate drought tolerance through summer dormancy, recovering when moisture returns.
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.5 inches. Requires regular mowing, moderate to high fertilization (2-4 lbs N per 1000 sq ft per year), periodic dethatching, and aeration. Overall maintenance level is medium to high.
Special Characteristics
Excellent wear tolerance and traffic recovery due to rhizomes. Good cold tolerance and winter color retention in milder cool zones, but prone to summer stress in hot climates. Moderate shade tolerance.
Ecological Information
Introduced species in North America. Provides standard lawn ecosystem and soil stabilization benefits. Often blended with Perennial Ryegrass and Fine Fescues to improve disease resistance and establishment speed.