Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae
Grass Category
Lawn/Turf Grass, Sports Turf
Variety / Cultivar
Standard turf-type varieties (e.g., 'Midnight', 'Compact Midnight')
Hardiness Zones
USDA Zones 3 to 7; excellent cold tolerance, moderate heat tolerance; can struggle in the deep southern transition zones without heavy irrigation.
About This Grass
Forms a dense, high-quality turf with medium-fine texture and rich medium to dark green color. Height ranges from 1.5 to 2.5 inches when maintained, but can reach 18 to 24 inches if unmowed. Produces panicle-type seed heads at maturity.
Blade Characteristics
Blades are medium width (2-4mm), flat to folded with distinct parallel veins and prominent boat-shaped tips. Vernation is folded in the bud. Ligule is short and membranous, with no auricles.
Root System
Moderately deep fibrous root system combined with vigorous rhizomes. Forms a very dense sod, moderate to slow establishment from seed, excellent self-repairing wear recovery through rhizomatous spread.
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 sod
Sunlight & Water Needs
Performs best in full sun (minimum 6 hours of direct sunlight); moderate to high water needs; good cold-season dormancy drought tolerance but goes summer dormant under prolonged severe drought; prefers well-drained loamy soils with pH 6.0-7.0.
Mowing & Maintenance
Mowing height between 2.0 to 3.0 inches; regular weekly mowing during peak growth; high fertilization requirements (3-5 lbs N per 1000 sq ft annually); moderate to high maintenance level requiring periodic dethatching and aeration.
Special Characteristics
High wear tolerance and excellent self-repair capability due to rhizomes; good winter color retention in milder climates; moderate disease susceptibility (e.g., dollar spot, leaf spot, summer patch); excellent erosion control.
Ecological Information
Introduced species in North America; provides standard turf ecosystem benefits including soil stabilization and runoff filtration; frequently blended with perennial ryegrass and fine fescues for lawns.