Annual bluegrass contains both annual and perennial species. Annual bluegrass forms dense patches that can withstand low mowing heights. Annual bluegrass has a boat-shaped tip, folded in the bud. The ligule is membranous and auricles are absent. Annual bluegrass has a small panicle seedhead. Germination occurs in late summer and early spring. Annual bluegrass is found throughout the United States and Canada.
Annual bluegrass cannot be controlled culturally. Both annual and perennial species of annual bluegrass exist, depending on where it's developing. Most annual bluegrass on greens is of the perennial species, while the annual species develops in fairways and lawn type settings. Both will fade out with hot summer temperatures. The perennial species will develop from the crowns of existing plants and seeds, while the annual species develop from germinating seeds in the fall. Annual bluegrass can adapt to all cutting heights. The seedhead will also develop under all cutting heights. Annual bluegrass excels with high fertility and irrigation.
Make a pre-emergence application in the fall and spring to prevent germination of annual bluegrass.