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, dense turf, and excellent disease resistance)
Hardiness Zones
Thrives in USDA Zones 3 to 7. Excellent cold tolerance, goes dormant in extreme heat unless irrigated, suitable for northern and northern transition zones.
About This Grass
Forms a dense, high-quality turf with medium-fine texture. Reaches 18-24 inches if unmowed, but maintained at 1.5-2.5 inches. Color ranges from medium to dark blue-green. Exhibits winter dormancy where it turns brown or straw-colored in harsh cold climates.
Blade Characteristics
Medium-fine width (2-3mm), flat to folded shape, distinctive boat-shaped tips, blue-green to dark green color. Folded vernation in the bud. Prominent parallel veins with a slight tramline effect. Ligule is short and membranous; auricles are absent.
Root System
Moderately deep fibrous root system with extensive rhizomes. Moderate to high thatch-forming tendency. Slow to moderate establishment speed from seed, but excellent long-term wear recovery via rhizomes.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America and temperate regions worldwide
Growth Habit
Aggressively rhizomatous, spreading underground to form a dense, uniform sod
Sunlight & Water Needs
Requires full sun (at least 6-8 hours daily), moderate to high water needs for optimal appearance, good drought dormancy capability but poor true drought tolerance without irrigation. 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 maintenance level needing 3-5 lbs N per 1000 sq ft per year, regular aeration, and occasional dethatching.
Special Characteristics
High traffic and wear tolerance once established, good recuperative ability via rhizomes, moderate shade tolerance compared to fine fescues, susceptible to summer patch and dollar spot if mismanaged, excellent winter color retention in milder northern zones.
Ecological Information
Introduced species in North America. Provides standard turf ecosystem services such as soil stabilization and carbon sequestration. Often blended with perennial ryegrass and fine fescues for balanced lawn establishment.