Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Likely a common turf-type blend or commercial cultivar (e.g., 'Midnight' or 'Baron'), though specific cultivar identification requires genetic testing
Hardiness Zones
USDA Zones 2-7. Excellent cold tolerance; enters winter dormancy and can survive sub-zero temperatures. Poor heat tolerance in the deep South.
About This Grass
Medium-textured turf with a rich green to dark blue-green color. It forms a lush, carpet-like mat and is known for its ability to self-repair via rhizomes. Seed heads are open, spreading panicles (pyramidal shape) when unmowed.
Blade Characteristics
Blade width is medium (2-4mm). The most defining feature is the boat-shaped (V-shaped) tip and two prominent parallel veins (trolley tracks) on the upper surface. Vernation is folded in the bud; ligule is short and membranous; auricles are absent.
Root System
Moderately shallow fibrous root system with extensive horizontal rhizomes. It has a significant thatch-forming tendency and slow establishment from seed but excellent long-term sod density.
Growing Information
Origin Region
Native to Europe, Northern Asia, and the mountains of Morocco and Algeria; widely naturalized across North America
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense, uniform sod
Sunlight & Water Needs
Full Sun preferred (minimum 6 hours); poor shade tolerance. High water needs (1-1.5 inches per week) to maintain green color during summer; will go dormant (brown) during drought to survive.
Mowing & Maintenance
Ideal height: 2.0-3.5 inches. High maintenance level. Requires frequent mowing and 2-4 lbs of nitrogen per 1000 sq ft per year. Needs periodic core aeration and dethatching.
Special Characteristics
Excellent wear tolerance and recovery due to rhizomes. Good salt tolerance. Susceptible to summer patch, dollar spot, and necrotic ring spot in high humidity/heat.
Ecological Information
Introduced and naturalized in North America. Provides good soil stabilization and erosion control. Often blended with Perennial Ryegrass or Fine Fescue to improve disease resistance and shade tolerance.