Kentucky Bluegrass
Poa pratensis · Cool-season Performance, Perennial, C3 Grass
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass and Naturalized Weed
Variety / Cultivar
Standard Wild-type / Common (Visual identification of specific cultivar is limited by sparse growth)
Hardiness Zones
USDA Zones 2-7; excellent cold hardiness; limited heat tolerance (struggles in deep South US).
About This Grass
A fine-to-medium textured grass with a characteristic deep emerald to blue-green color. In the photo, it appears as immature, scattered patches struggling in compacted, sandy soil. When mature and unmanaged, it reaches 12-24 inches with open, airy panicle seed heads.
Blade Characteristics
Width: 2-4mm (medium); Shape: V-shaped or flat; Tip: Distinctive boat-shaped (keeled) tip; Color: Dark green with a prominent midrib; Vernation: Folded in the bud; Ligule: Short, membranous, and truncated; Auricles: Absent.
Root System
Moderately deep fibrous root system supported by an extensive network of rhizomes. High thatch-forming tendency; slower to establish from seed compared to ryegrass but provides excellent sod stability.
Growing Information
Origin Region
Native to Europe, North Asia, and Northern Africa; naturalized across North America, performing best in temperate humid climates.
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense sod under ideal conditions, though currently appearing as sparse, opportunistic sprouts.
Sunlight & Water Needs
Requires Full Sun (6+ hours) for best density; moderate shade tolerance. High water needs; will enter summer dormancy (turn brown) during severe drought to protect the rhizomes.
Mowing & Maintenance
Ideal height: 2.0-3.5 inches. High maintenance requirement: Needs 2-4 lbs of Nitrogen per 1000 sq ft annually, regular aeration to manage thatch, and supplemental irrigation.
Special Characteristics
Excellent wear recovery due to rhizomes; susceptible to leaf spot, melting out, and necrotic ring spot; high salt sensitivity; dormant in winter and extreme summer heat.
Ecological Information
Introduced/Naturalized in North America; provides forage for various lepidoptera larvae; excellent soil stabilizer for erosion control once established; commonly blended with Perennial Ryegrass and Fine Fescue.