A native European, Asian, Moroccan and Algerian grass, Kentucky bluegrass gets its name from the bluish hue the grass has from a distance. Kentucky bluegrass (Poa pratensis) belongs to the Poaceae family and is one of the most widely used grass species throughout North America, Hawaii and Puerto Rico. In the United States, it is considered an invasive weed in Wisconsin and the Great Plains States; proper management is important in controlling its spread. Kentucky Bluegrass has many characteristics that help it thrive in North America, especially in cool and humid areas.
A low-growing grass, Kentucky bluegrass can grow 18 to 24 inches tall at mature height. Kentucky bluegrass does not form very deep roots, meaning it is not a good soil stabilizer; its shallow roots only reach 8 centimeters into the soil. The foliage is green with a blue tone, and its flowers are yellow. The flowers will emerge from the grass if it is left uncut. The seeds produced are brown.
Kentucky bluegrass is a slow-growing perennial plant with a moderate growth rate. It grows and spreads in a rhizomatous pattern--through its underground stems. While it has a long lifespan, it takes two to three years to become established and to eventually develop into a dense sod, according to the United States Department of Agriculture.
Kentucky bluegrass is generally intolerant to shade. However, some cultivars, including Glade, Nugget and Bristol, have moderate shade tolerance. Kentucky bluegrass can grow in fine- to medium-textured soils. It has a high tolerance for calcium carbonate (CaCO3) in the soil but a low tolerance to salt. It requires a soil pH range of 5.0 to 8.4. Kentucky bluegrass requires moderate watering and cannot tolerate extreme water conditions like drought or flooding. It grows well in well-drained soils.