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 (fairways and tees)
Variety / Cultivar
General species representation (commonly cultivars like 'Midnight' or 'Compact') known for deep blue-green color and dense sod formation.
Hardiness Zones
Thrives in USDA Hardiness Zones 3 through 7. Excellent cold tolerance, surviving sub-zero winter temperatures. Performs poorly in extreme southern heat unless heavily irrigated.
About This Grass
Forms a dense, high-quality turf with a medium to fine texture. Height ranges from 1.5 to 2.5 inches when maintained as a lawn, but can reach 18 to 24 inches if unmowed. Color is characteristically rich green to dark blue-green. Exhibits winter dormancy in extremely cold climates, turning brown or straw-colored.
Blade Characteristics
Blades are medium width (2-4mm), flat or folded in the bud with a distinct boat-shaped tip. Prominent parallel veins and a clear midrib. Vernation is folded. Ligule is short and membranous; auricles are absent.
Root System
Moderately deep fibrous root system combined with an extensive network of underground rhizomes. Can form a thick thatch layer if not properly managed. Moderate establishment speed (slow to germinate from seed). High wear recovery due to aggressive rhizomatous spread.
Growing Information
Origin Region
Native to Europe, northern Asia, and parts of the mountainous regions of North America. Widely cultivated throughout the northern United States, Canada, and cool regions worldwide.
Growth Habit
Rhizomatous (spreading aggressively via underground stems), forming a dense, uniform, and tight turf mat.
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily), with poor tolerance for deep shade. Moderate to high water needs to maintain lush green color during hot summer months; goes into summer dormancy under severe drought. 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 regular mowing during peak spring and fall growth periods. High fertilization needs (2-4 lbs N per 1,000 sq ft per year). Regular dethatching and annual core aeration are recommended. High maintenance level.
Special Characteristics
Exceptional wear tolerance and ability to self-repair via rhizomes. Moderate shade tolerance (better in northern climates). Prone to certain diseases like dollar spot, summer patch, and powdery mildew under high stress and humidity. Excellent erosion control due to dense root and rhizome mat.
Ecological Information
Introduced species in North America. Provides limited wildlife habitat mostly as a grazing source for herbivores and nesting cover for ground birds. High erosion control and soil stabilization capabilities. Commonly blended with perennial ryegrass and fine fescues in seed mixtures to improve establishment speed and disease resistance.