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
General commercial type (e.g., 'Midnight', 'Baron')
Hardiness Zones
USDA Hardiness Zones 3 to 7 (performs exceptionally well in northern climates and the cooler parts of the transition zone). Excellent cold hardiness, going dormant during freezing winters.
About This Grass
Forms a lush, dense, dark green to blue-green turf with a fine to medium texture. Unmowed height reaches 18 to 24 inches with distinctive pyramid-shaped panicle seed heads, but is typically maintained at 1.5 to 2.5 inches. Exhibits moderate to high density and excellent wear recovery due to aggressive rhizome spread.
Blade Characteristics
Blades are fine to medium in width (2-4mm), flat to folded with prominent 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 is broad and continuous.
Root System
Moderate depth (6-12 inches) fibrous root system combined with an extensive network of strong underground rhizomes. Moderate to high thatch-forming tendency under high fertility and moisture. Slow to moderate establishment speed from seed.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America and temperate regions worldwide
Growth Habit
Rhizomatous (spreading aggressively via underground stems) forming a dense sod and turf mat
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily) for best performance, though some cultivars offer moderate shade tolerance. High water needs during hot dry spells to prevent summer dormancy; fair to good drought tolerance by going dormant during severe drought and recovering upon watering. Prefers well-drained, fertile soils with a pH between 6.0 and 7.0.
Mowing & Maintenance
Ideal mowing height is 1.5 to 2.5 inches. Requires frequent mowing during peak spring and fall growth periods. High maintenance level requiring 3-4 lbs of nitrogen per 1000 sq ft annually, regular irrigation, and periodic dethatching and core aeration.
Special Characteristics
Exceptional traffic and wear tolerance due to aggressive rhizomatous self-repair. Good cold and freezing tolerance. Moderate disease susceptibility (e.g., leaf spot, dollar spot, summer patch). Excellent erosion control and weed suppression due to dense sod formation.
Ecological Information
Introduced species in North America. Provides good soil stabilization, water filtration, and turf cover. Often blended with Perennial Ryegrass and Fine Fescues to create resilient turfgrass mixtures for residential and commercial landscapes.