Kentucky Bluegrass
Poa pratensis · Cool-season (C3), Perennial
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Likely a common mixed turf blend (e.g., 'Midnight' or 'Baron' heritage), given the residential setting and visible color/texture
Hardiness Zones
USDA Hardiness Zones 2 through 7. Excellent cold tolerance; enters dormancy in the transition zone during hot summers (Zone 7).
About This Grass
A dense, low-growing turf grass with a characteristic dark green to blue-green color. In the image, it shows a medium-to-high density with a fine-to-medium texture. It remains dormant/brown in extreme heat or bitter cold but recovers quickly in spring and fall.
Blade Characteristics
Fine to medium width (2-4mm); characteristic boat-shaped (keeled) leaf tips; vernation is folded in the bud; leaves are smooth with parallel veins and a prominent midrib (twin mid-veins visible under magnification); ligule is very short and membranous; auricles are absent.
Root System
Fibrous and rhizomatous system. The roots are moderately shallow compared to fescues, but the rhizomes create a very strong, tight sod layer that is effective for erosion control but prone to thatch buildup if over-fertilized.
Growing Information
Origin Region
Native to Europe, North Asia, and the mountains of Morocco and Algeria; highly adapted to northern temperate climates in North America
Growth Habit
Rhizomatous (spreading via underground stems). Forms a dense, thick sod that is capable of self-repairing bare spots through lateral expansion.
Sunlight & Water Needs
Prefers Full Sun (6+ hours) but can tolerate light partial shade. High water needs; it will go dormant during summer droughts to protect the crown. Performs best in well-drained, fertile soils with a pH between 6.0 and 7.5.
Mowing & Maintenance
Ideal height 2.5 to 3.5 inches; maintenance is medium to high. Requires 3-5 lbs of Nitrogen per 1000 sq ft annually for optimal density. Core aeration and dethatching every 1-2 years.
Special Characteristics
Excellent wear tolerance and recovery due to rhizomes; produces a high-quality 'carpet-like' finish; moderate disease resistance but susceptible to summer patch and dollar spot in high humidity.
Ecological Information
Introduced and naturalized in North America. Used extensively for soil stabilization and water filtration in urban landscapes. Often blended with Perennial Ryegrass for faster establishment or Fine Fescue for shade adaptation.