Kentucky Bluegrass
Poa pratensis · Cool-season perennial (C3)
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Common lawn mix (likely includes Midnight or similar darker green cultivars)
Hardiness Zones
USDA Zones 2-7; excellent cold tolerance (survives harsh winters); enters protective dormancy during extreme heat or drought.
About This Grass
A medium-textured, dark green turfgrass that forms a lush, uniform lawn. It grows significantly denser than fescues due to its rhizomes. In residential settings, it is typically maintained at 2-3 inches, exhibiting a deep blue-green hue during spring and fall.
Blade Characteristics
Blade width is medium (2-4mm). The most defining feature is the boat-shaped leaf tip. Blades are smooth, with a distinct center vein (midrib) and folded vernation. Ligules are short and membranous; auricles are absent.
Root System
Relatively shallow fibrous root system with extensive horizontal rhizomes. It has a high thatch-forming tendency but excellent self-repairing capabilities due to its spreading nature.
Growing Information
Origin Region
Europe, Northern Asia, and North Africa; now dominant in North American temperate regions
Growth Habit
Rhizomatous (spreading underground); forms a thick, dense sod-forming mat
Sunlight & Water Needs
Prefers full sun (minimum 6 hours) but has moderate shade tolerance. High water requirement compared to fescues; needs consistent moisture particularly during summer heat to avoid dormancy.
Mowing & Maintenance
Maintain at 2.5 to 3.5 inches. High maintenance level; requires 2-4 lbs of Nitrogen per 1000 sq ft annually. Requires periodic dethatching and aeration due to rhizome buildup.
Special Characteristics
Excellent traffic/wear tolerance and recovery due to rhizomes. Susceptible to leaf spot, melting out, and necrotic ring spot during humid conditions. Very soft texture compared to Tall Fescue.
Ecological Information
Introduced and naturalized in North America. Provides stabilization for soil and high-quality filtration for urban runoff. Often blended with Perennial Ryegrass and Fine Fescues for genetic diversity.