Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf and Pasture grass
Variety / Cultivar
Common or Unknown (possibly a mix including older cultivars like 'Kenblue')
Hardiness Zones
USDA Zones 2-7; excellent cold tolerance; enters summer dormancy during extreme heat/drought; not well-suited for the deep South.
About This Grass
Medium-textured turf grass with a distinct dark green to blue-green color. It is currently appearing somewhat thin and dormant in the image with brown lower stems. When unmowed, it reaches 12-24 inches with open, pyramidal panicle seed heads.
Blade Characteristics
Blade width is medium (2-4mm); characteristic 'boat-shaped' (keeled) leaf tips; folded vernation; prominent central vein (midrib); ligule is short and membranous; auricles are absent.
Root System
Relatively shallow to moderate fibrous root system supported by a dense network of rhizomes; has a high thatch-forming tendency; slow to establish from seed but excellent at self-repairing.
Growing Information
Origin Region
Europe, Northern Asia, and the mountains of Morocco; widely naturalized across North America
Growth Habit
Rhizomatous (spreading underground); forms a dense, tight-knit sod over time via horizontal underground stems
Sunlight & Water Needs
Prefers Full Sun (6+ hours); moderate shade tolerance; requires regular watering during summer to prevent dormancy; prefers well-drained, slightly acidic to neutral soil (pH 6.0-7.0).
Mowing & Maintenance
Ideal height 2.5 to 3.5 inches; high maintenance; requires 2-4 lbs of Nitrogen per 1000 sq ft annually; needs periodic dethatching and core aeration.
Special Characteristics
High wear tolerance due to rhizomes; excellent winter hardiness; susceptible to leaf spot, melting out, and necrotic ring spot; slow germination rate (21-28 days).
Ecological Information
Introduced and naturalized in North America; provides forage for livestock and nesting cover for small birds; often used in 80/20 mixes with Perennial Ryegrass to improve durability.