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, dense growth, and good disease resistance)
Hardiness Zones
USDA Hardiness Zones 3 to 7, excellent cold tolerance, moderate heat tolerance, often used in northern regions and cool transition zones.
About This Grass
Forms a dense, medium-fine textured turf with a rich blue-green to dark green color. Height ranges from 1.5 to 2.5 inches when maintained, and up to 18-24 inches if left unmowed. Produces open, pyramidal panicle seed heads at maturity.
Blade Characteristics
Medium-fine width (3-4mm), flat to folded shape with distinct parallel veins and a prominent boat-shaped tip. Vernation is folded in the bud. Ligule is short and membranous, auricles are absent.
Root System
Moderately deep fibrous root system with extensive underground rhizomes. Forms a very dense sod, medium establishment speed, moderate to high thatch-forming tendency.
Growing Information
Origin Region
Europe, northern Asia, and parts of the mountainous regions of North America. Well-adapted throughout the northern United States and Canada.
Growth Habit
Rhizomatous, spreading extensively via underground stems to form a dense, uniform turf mat.
Sunlight & Water Needs
Requires full sun (at least 6-8 hours daily), moderate to high water needs, fair drought tolerance through summer dormancy, 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. Fertilization requirement is medium to high (3-5 lbs N per 1000 sq ft annually). Requires regular dethatching and aeration, high maintenance level.
Special Characteristics
Excellent wear tolerance and remarkable ability to recover from damage due to rhizomatous spreading. Good cold tolerance, moderate shade tolerance compared to fine fescues, susceptible to certain diseases like dollar spot and leaf spot under stress.
Ecological Information
Introduced species in North America, provides excellent soil stabilization and erosion control due to dense root and rhizome matrix. Frequently blended with perennial ryegrass and fine or tall fescues in turf seed mixes.