Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf
Variety / Cultivar
Common blend containing standard turf cultivars (such as 'Midnight' or 'Baronie')
Hardiness Zones
Thrives in USDA Hardiness Zones 3 through 7. Excellent cold tolerance, surviving severe winters, but goes dormant and turns brown during extreme summer heat unless irrigated.
About This Grass
Forms a dense, medium-textured turf with a rich dark green to blue-green color. Maintained height is typically 2 to 3 inches, while unmowed growth can reach 18 to 24 inches with pyramidal, open panicle seed heads. High density and excellent self-repairing capabilities due to aggressive rhizomes.
Blade Characteristics
Medium width (3-4mm), flat to folded shape with distinct boat-shaped tips and prominent parallel veins giving a tramline appearance. Vernation is folded in the bud. Ligule is short and membranous, and auricles are absent.
Root System
Moderately deep fibrous root system combined with strong underground rhizomes. Forms a very dense sod, has moderate thatch-forming tendencies, and exhibits medium-slow establishment from seed.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America and cool 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, requiring at least 6 to 8 hours of direct sunlight daily; has moderate shade tolerance depending on the cultivar. Requires regular moisture (approx. 1 inch of water per week) and has moderate drought tolerance, entering dormancy during prolonged dry spells.
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.0 inches. Requires frequent mowing during peak spring and fall growth periods. Medium to high maintenance level, needing 2 to 4 lbs of nitrogen per 1,000 sq ft annually, along with periodic dethatching and core aeration.
Special Characteristics
Exhibits exceptional wear tolerance and self-repairing capability via rhizomes. Good cold hardiness and winter color retention in milder cool climates. Moderate susceptibility to diseases like summer patch, dollar spot, and rust under high humidity and improper fertilization.
Ecological Information
Introduced to North America by European settlers. Provides standard lawn ecosystem and soil stabilization benefits. Frequently blended with Perennial Ryegrass and Fine Fescues to improve disease resistance, establishment speed, and adaptability.