Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Grass Category
Lawn/Turf Grass and Sports Turf
Variety / Cultivar
Midnight (or common commercial blend)
Hardiness Zones
USDA Hardiness Zones 3 to 7. Excellent cold tolerance, goes semi-dormant or brown during extreme summer heat unless irrigated.
About This Grass
Forms a dense, high-quality turf with medium-fine texture and rich green to dark blue-green color. Grows 18 to 24 inches tall if left unmowed, but maintained at 1.5 to 2.5 inches. Produces open, pyramidal panicle seed heads at maturity.
Blade Characteristics
Blades are medium width (2-4mm), flat to folded, with characteristic boat-shaped tips. Vernation is folded in the bud. Ligule is short and membranous, auricles are absent, and the collar is broad and continuous.
Root System
Moderately deep fibrous root system combined with strong rhizomes. Forms a very dense sod that has good wear recovery but moderate drought vulnerability during extreme summer dormancy.
Growing Information
Origin Region
Europe and Northern Asia; widely naturalized and cultivated across North America, performing best in northern temperate regions.
Growth Habit
Rhizomatous, spreading extensively via underground stems to form a dense, uniform turf mat.
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours daily) and prefers moist, fertile, well-drained soils with a pH of 6.0 to 7.0. Moderate to high water needs; goes dormant during prolonged drought.
Mowing & Maintenance
Maintain mowing height between 2.0 and 3.5 inches. High maintenance level requiring regular fertilization (3-4 lbs N per 1000 sq ft annually), frequent mowing, and periodic dethatching and aeration.
Special Characteristics
Excellent traffic and wear tolerance due to aggressive rhizomes, good cold hardiness, moderate disease susceptibility (such as dollar spot and leaf spot), poor shade tolerance compared to fescues.
Ecological Information
Introduced to North America by European settlers. Used extensively in lawn seed mixtures with perennial ryegrass and fescues. Provides standard turf ecosystem benefits including soil stabilization and runoff filtration.