Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Common lawn-grade cultivar (likely a blend including Midnight or Baron types)
Hardiness Zones
USDA Zones 2-7. Excellent cold tolerance. Enters summer dormancy in heat and winter dormancy in freezing temperatures.
About This Grass
A medium-textured turfgrass with a distinct dark green to blue-green color. It forms a lush, uniform carpet and is known for going dormant (turning brown/straw-colored) during extreme heat and drought to survive, as seen in the center of the image.
Blade Characteristics
Narrow to medium blades (2-4mm), folded vernation in the bud, and iconic boat-shaped (V-shaped) leaf tips. Leaf surface is smooth with a prominent midrib (keel). Ligule is short and membranous; auricles are absent.
Root System
Relatively shallow fibrous root system compared to fescue, but supplemented by strong rhizomes that allow for self-repair and high sod density. High thatch-forming tendency.
Growing Information
Origin Region
Europe, North Asia, and Northern Africa; naturalized throughout North America
Growth Habit
Rhizomatous (underground spreading) forming a dense, thick sod
Sunlight & Water Needs
Prefers full sun (minimum 6 hours) but has moderate shade tolerance. High water requirements; requires regular irrigation to stay green during summer months. Prefers well-drained soil with pH 6.0-7.0.
Mowing & Maintenance
Ideal height 2.5–3.5 inches. High maintenance level. Requires 2-4 lbs of Nitrogen per 1000 sq ft annually and periodic dethatching/core aeration due to rhizome spread.
Special Characteristics
Excellent wear tolerance and recovery due to rhizomes. Susceptible to summer patch, dollar spot, and necrotic ring spot. Highly valued for aesthetic appeal and soft texture.
Ecological Information
Introduced species in North America. Provides high soil stabilization and erosion control. Often mixed with Perennial Ryegrass or Fine Fescue for improved diversity and disease resistance.