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
Common or Elite type (requires closer inspection of seed source for specific cultivar such as 'Midnight' or 'Mazama')
Hardiness Zones
USDA Zones 2-7; excellent cold tolerance, enters winter dormancy in freezing temperatures, poor performance in high-heat humid climates (deep South).
About This Grass
A dense, mat-forming perennial grass that maintains a medium to dark green color. Reaches 12-24 inches if unmowed, exhibiting a soft, lush texture and panicle-type seed heads that are open and pyramid-shaped.
Blade Characteristics
Blade width is medium (2-4mm); features a distinct boat-shaped tip, folded vernation in the bud, and a smooth, dull underside. Color is typically deep blue-green with a prominent midrib (central vein) and two clear lines on either side of it.
Root System
Moderately deep fibrous root system with extensive rhizomes; known for high thatch tendency but excellent sod-forming ability and recovery from wear.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized in North America, particularly in the northern United States and Canada
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense, self-repairing sod with a medium growth rate
Sunlight & Water Needs
Prefers Full Sun (6+ hours) but can tolerate light shade; requires consistent watering (1 inch per week) and has moderate drought tolerance (enters dormancy during heat/drought).
Mowing & Maintenance
Mowing height 2.5 to 3.5 inches; moderate to high maintenance including 2-4 lbs Nitrogen per 1000 sq ft annually and periodic dethatching/core aeration.
Special Characteristics
Exceptional wear tolerance and self-healing ability due to rhizomes; susceptible to leaf spot, melting out, and dollar spot; provides the classic 'perfect lawn' look.
Ecological Information
Introduced and naturalized; provides cover for small mammals and birds; highly valued for soil erosion control on slopes; often blended with Perennial Ryegrass or Fine Fescue for genetic diversity.