Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae
Grass Category
Lawn/Turf Grass, Sports Turf, Golf Course Grass
Variety / Cultivar
General species type ('Midnight' or similar dark green turf cultivars)
Hardiness Zones
USDA Hardiness Zones 3 to 7, exceptionally cold tolerant, prone to summer stress in hot southern climates outside the transition zone, goes dormant during severe winter freezes.
About This Grass
Forms a dense, fine-to-medium textured turf with a rich dark green to blue-green color. Mown height typically maintained at 1.5 to 2.5 inches, while unmowed seed heads can reach 18 to 24 inches with an open panicle structure.
Blade Characteristics
Blades are medium-fine (2-4mm wide), flat to folded in the bud with distinctive boat-shaped tips. Prominent parallel veins with a light-colored midrib groove. Ligule is short and membranous, auricles absent, collar is narrow and continuous.
Root System
Moderately deep fibrous root system combined with extensive rhizomes. Moderate establishment speed from seed, forms a very dense sod that holds soil well and recovers well from wear via rhizomes.
Growing Information
Origin Region
Europe, northern Asia, and parts of the mountainous regions of North America. Widely cultivated globally in cool-temperate regions.
Growth Habit
Rhizomatous, spreading underground via aggressive creeping rhizomes to form a dense, uniform turf mat.
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily) for optimal growth, moderate to high water needs, fair to good drought tolerance by entering summer dormancy, prefers well-drained fertile soils with a pH of 6.0 to 7.0.
Mowing & Maintenance
Mow at 1.5 to 2.5 inches. High maintenance requirement, needs regular fertilization (3-5 lbs N per 1,000 sq ft annually), frequent irrigation during dry spells, and occasional dethatching due to dense rhizome production.
Special Characteristics
Excellent traffic and wear tolerance, good recovery due to spreading rhizomes, moderate shade tolerance compared to fine fescues, susceptible to certain diseases like dollar spot and leaf spot under high nitrogen and humidity.
Ecological Information
Introduced to North America by early European settlers. Provides standard lawn ecosystem services, low wildlife food value compared to native prairies, excellent for erosion control and dust reduction in urban/suburban landscapes.