Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3
Grass Family
Poaceae, Subfamily Pooideae, Tribe Poeae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Common or 'Midnight' type (Generic Bluegrass Blend)
Hardiness Zones
USDA Zones 2-7; excellent cold hardiness; poor performance in the deep South due to heat intolerance.
About This Grass
A dark green, high-quality turf grass with a fine to medium texture. Grows 12-24 inches if left unmowed. It form a lush, thick carpet that goes dormant (brown) during heat and drought but recovers quickly when conditions improve. Seed heads are open, pyramidal panicles.
Blade Characteristics
Narrow blades (2-4mm), V-shaped or flat, featuring a distinct 'boat-shaped' tip. Vernation is folded in the bud. Color ranges from deep emerald to blue-green. Ligule is short and membranous; auricles are absent.
Root System
Moderately shallow fibrous root system supplemented by extensive rhizomes. Forms significant thatch over time; establishment is slow (14-21 days to germinate).
Growing Information
Origin Region
Europe, Northern Asia, and North Africa; now dominant in Northern US and Canada
Growth Habit
Rhizomatous (spreading via underground stems), forming a dense, self-repairing sod
Sunlight & Water Needs
Full sun preferred (6+ hours); moderate shade tolerance. High water requirements; requires regular irrigation during summer to prevent dormancy. Prefers well-drained soil with pH 6.0-7.5.
Mowing & Maintenance
1.5 to 3.0 inches; high maintenance level. Requires 3-5 lbs of Nitrogen per 1000 sq ft annually. Benefits greatly from core aeration and dethatching every 1-2 years.
Special Characteristics
Excellent wear tolerance and recovery due to rhizomes. Susceptible to leaf spot, melting out, and necrotic ring spot. Highly prized for aesthetic beauty and soft feel.
Ecological Information
Introduced and naturalized in North America. Provides low wildlife value in mowed lawns but can provide forage for grazing animals in pastures. Often mixed with Perennial Ryegrass and Fine Fescues for genetic diversity.