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' or similar dark green elite cultivars, known for deep color and dense growth
Hardiness Zones
USDA Hardiness Zones 3 to 7, excellent cold tolerance, moderate heat tolerance, goes dormant and turns brown under severe summer heat or drought conditions.
About This Grass
Forms a dense, medium-textured, rich green turf with high wear tolerance due to aggressive spreading rhizomes. Height ranges from 1.5 to 2.5 inches when maintained, but can reach 18-24 inches if left unmowed, producing pyramid-shaped panicle seed heads.
Blade Characteristics
Medium-fine width (2-3mm), flat to folded shape with distinctive boat-shaped tips. Color ranges from medium to dark or blue-green. Vernation is folded in the bud with prominent parallel veins and a slight keel. Ligule is short and membranous; auricles are absent.
Root System
Moderately deep fibrous root system combined with aggressive underground rhizomes. Forms a very dense sod that holds soil exceptionally well, though it has moderate establishment speed.
Growing Information
Origin Region
Europe and Northern Asia, widely naturalized and cultivated across North America and 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 daily), requires regular moisture during dry periods, moderate drought tolerance by entering 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. Requires medium-high maintenance including regular mowing, 2-4 lbs N per 1000 sq ft per year fertilization, periodic aeration and dethatching, and overseeding when necessary.
Special Characteristics
Exceptional wear tolerance and self-repairing capability via rhizomes. Moderate shade tolerance (prefers full sun). Good disease resistance depending on the specific cultivar. Excellent choice for high-traffic lawns and sports fields.
Ecological Information
Introduced to North America by European settlers. Provides standard lawn ecosystem services, stabilizes topsoil against erosion, creates micro-habitats for beneficial insects, and is frequently blended with Perennial Ryegrass and Fine Fescues.