Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass, Sports Turf
Variety / Cultivar
Standard or common blend (e.g., 'Midnight' or 'Baronie')
Hardiness Zones
USDA Hardiness Zones 3 to 7, tolerates cold winters very well, enters dormancy during extreme summer heat, performs exceptionally well in northern and transition zones.
About This Grass
Forms a dense, high-quality turf with a medium-fine texture and a rich dark green to blue-green color. Mows cleanly and maintains upright growth. Height reaches 18 to 24 inches if unmowed, but maintained at 1.5 to 2.5 inches in lawns. Produces open, pyramidal panicle seed heads at maturity.
Blade Characteristics
Blades are medium width (2-4mm), flat with distinct parallel veins, and feature characteristic boat-shaped tips. Vernation is folded in the bud. Ligule is short and membranous, and auricles are absent.
Root System
Moderate to deep fibrous root system combined with vigorous underground rhizomes. Forms a very dense sod, moderate thatch tendency, slow to moderate establishment from seed, excellent wear recovery due to spreading rhizomes.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America and cool temperate regions worldwide
Growth Habit
Rhizomatous, spreading extensively via underground stems to form a dense turf mat
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours direct sunlight) for optimal growth, though some shade-tolerant cultivars exist. High water needs to maintain green color during dry spells; goes into summer dormancy under drought conditions. Thrives in well-drained, fertile soils with a pH of 6.0 to 7.0.
Mowing & Maintenance
Ideal mowing height is 2.0 to 3.5 inches. Requires frequent mowing during peak spring/fall growth. High fertilizer requirement (3-4 lbs N per 1000 sq ft annually). Needs periodic dethatching and aeration. High maintenance level.
Special Characteristics
High traffic and wear tolerance due to aggressive spreading via rhizomes. Good cold tolerance, moderate drought tolerance via dormancy, excellent self-repairing capabilities, susceptible to certain diseases like dollar spot and leaf spot under high humidity.
Ecological Information
Introduced species in North America. Provides moderate wildlife food and nesting cover. Excellent soil stabilization and erosion control due to dense sod and rhizome network. Commonly blended with perennial ryegrass and fine fescues in northern turf seed mixes.