Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 pathway
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Common or 'Midnight' type (Generic Turf-type)
Hardiness Zones
USDA Zones 2-7; excellent cold tolerance; poor performance in high-heat humid Southern climates.
About This Grass
A dark green to blue-green turf grass with a fine to medium texture. It grows to 6–12 inches unmowed but is traditionally maintained at low heights. It features open, pyramid-shaped panicle seed heads when allowed to flower.
Blade Characteristics
Fine to medium width (2-4mm); flat or slightly folded; prominent boat-shaped (V-shaped) tip characteristic of Poa genus; dark green color; folded vernation; ligule is short and membranous; auricles are absent.
Root System
Moderately deep fibrous root system complemented by extensive rhizomes. Forms heavy thatch; slow to moderate establishment speed but excellent recovery via rhizomes.
Growing Information
Origin Region
Native to Europe, North Asia, and the mountains of Morocco and Algeria; highly adapted to temperate climates globally
Growth Habit
Rhizomatous; forms a thick, dense sod by spreading through underground stems
Sunlight & Water Needs
Full sun preferred (minimum 6 hours); moderate shade tolerance. High water requirements; enters summer dormancy during severe drought to protect crowns.
Mowing & Maintenance
Ideal height 2.5 to 3.5 inches; weekly frequency; requires 2-4 lbs N per 1000 sq ft annually; high maintenance due to dethatching and irrigation needs.
Special Characteristics
Excellent wear tolerance and recovery due to rhizomes; susceptible to leaf spot and necrotic ring spot; high aesthetic value for residential lawns and sports fields.
Ecological Information
Introduced and naturalized in North America; provides forage for various insects and small mammals; used often in mixes with Perennial Ryegrass and Fine Fescue (note: image shows significant infestation of Hydrocotyle/Dollarweed).