Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Likely a blend such as 'Midnight' or 'Baron' (Common in residential turf)
Hardiness Zones
USDA Zones 3-7; Excellent cold tolerance; enters dormancy during extreme heat or winter cold.
About This Grass
A medium-textured, dark green grass that forms a soft, dense turf. It goes semi-dormant (browning) during hot, dry summer periods as seen in the center of the image. Seed heads are open, pyramidal panicles.
Blade Characteristics
Width: medium (2-4mm); Shape: V-shaped or flat; Tip: distinct boat-shaped tip; Color: dark green to blue-green; Vernation: folded in the bud; Ligule: short, membranous; Auricles: absent; Collar: divided by a prominent midvein.
Root System
Relatively shallow fibrous root system with extensive horizontal rhizomes. High thatch tendency. Moderate establishment speed (slow germination but good spreading).
Growing Information
Origin Region
Native to Europe, North Asia, and the mountains of Algeria and Morocco; naturalized throughout North America
Growth Habit
Rhizomatous (spreading underground); forms a dense, thick sod-forming mat
Sunlight & Water Needs
Full Sun (minimum 6 hours); Water: High (needs regular irrigation to stay green in summer); Drought Tolerance: Moderate (goes dormant to survive, then recovers); pH: 6.0-7.0.
Mowing & Maintenance
Mowing height: 2.0-3.5 inches; Frequency: weekly during growth; Fertilization: 2-4 lbs N/1000 sq ft/year; Maintenance Level: High (requires regular water and food).
Special Characteristics
Excellent wear tolerance and recovery due to rhizomes; high aesthetic quality; good disease resistance in newer cultivars; poor shade tolerance.
Ecological Information
Introduced/Naturalized; provides soil stabilization for erosion control; serves as forage for wildlife; often mixed with Perennial Ryegrass or Fine Fescue for genetic diversity.