Kentucky Bluegrass
Poa pratensis · Cool-season Perennial (C3)
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Standard Common Variety (e.g., 'Kenblue')
Hardiness Zones
USDA Hardiness Zones 2 through 7; poor performance in the deep South due to heat intolerance. Highly cold-tolerant; enters winter dormancy and turns tan in freezing temperatures.
About This Grass
A medium-textured, cool-season grass with a soft feel. It features a characteristic rich green to blue-green color. It forms a dense, uniform carpet when well-maintained but can appear somewhat ragged or sparse if neglected in heat. Seed heads are open, airy panicles resembling small Christmas trees.
Blade Characteristics
Bades are 2-4mm wide (medium), smooth, and distinctly boat-shaped at the tip. They have a narrow, folded vernation. The color is typically deep green to blue-green. Ligules are short and membranous; auricles are absent. A prominent 'mid-rib' or 'track' is often visible down the center of the leaf.
Root System
Produces extensive underground rhizomes that allow for self-repair and dense sod formation. Rooting depth is typically shallow to moderate (6-10 inches), leading to moderate drought tolerance. Fast establishment from seed but slower than ryegrasses.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized in North America and temperate climates globally
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense sod or mat over time
Sunlight & Water Needs
Requires full sun to light shade (at least 6 hours of direct sun). High water needs during hot dry spells; will go dormant (brown) to survive extreme drought. Prefers well-drained, fertile soils with a pH between 6.0 and 7.5.
Mowing & Maintenance
Ideal height is 2.5 to 3.5 inches. Requires frequent mowing during peak spring and fall growth. Fertilization: 2-4 lbs Nitrogen per 1000 sq ft per year. High maintenance level due to water and nutrient requirements and potential thatch buildup.
Special Characteristics
Excellent wear tolerance and recovery due to rhizomes. Good disease resistance in modern cultivars, though susceptible to necrotic ring spot and summer patch. Notable for its beautiful color and soft texture underfoot.
Ecological Information
Introduced and naturalized in North America; provides forage for various wildlife and insects. Effectively stabilizes soil through its thick rhizomatous mat. Widely used in mixtures with perennial ryegrass and fine fescues for genetic diversity.