Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Common or 'Midnight' type (likely a blend including newer elite cultivars based on density)
Hardiness Zones
USDA Zones 2-7; excellent cold tolerance, moderate heat tolerance, often going dormant during extreme summer heat or winter cold.
About This Grass
A dense, mat-forming turf with a rich green to blue-green color. It exhibits a fine-to-medium texture and reaches a height of 12-24 inches if left unmowed. In summer heat, it may enter semi-dormancy, turning brown until cooler weather returns.
Blade Characteristics
Blade width is medium (2-4mm) with a distinctive boat-shaped (keeled) tip. The leaf is folded in the bud (folded vernation). The color is characteristically dark green or blue-green. It features a short, membranous ligule and no auricles.
Root System
Moderately deep fibrous root system complemented by extensive rhizomes. It produces significant thatch over time. Establishment speed is slow from seed (14-21 days to germinate) but creates the most durable sod once established.
Growing Information
Origin Region
Native to Europe and Northern Asia; widely naturalized across North America in temperate regions
Growth Habit
Rhizomatous (spreading underground via rhizomes), forming a dense, self-repairing sod
Sunlight & Water Needs
Full Sun preferred; requires at least 6 hours of direct sunlight. Moderate to high water needs; requires supplemental irrigation during dry spells to maintain green color. Prefers well-drained soil with a pH of 6.0-7.0.
Mowing & Maintenance
Ideal height is 2.0 to 3.5 inches. High maintenance level; requires 3-5 lbs of Nitrogen per 1000 sq ft annually. Requires core aeration and dethatching every 1-3 years due to rhizomatous growth.
Special Characteristics
Exceptional wear tolerance and self-recovery via rhizomes. Moderate shade tolerance. Prone to Dollar Spot, Summer Patch, and Leaf Spot. Noted for its soft feel underfoot and lush aesthetic appearance.
Ecological Information
Introduced and widely naturalized in North America. Provides soil stabilization and erosion control. Often blended with Perennial Ryegrass and Fine Fescues to improve disease resistance and shade adaptation in residential lawns.