Kentucky bluegrass is attractive, durable and grows just about anywhere but in deep shade, deserts or tropical shores. Although not originally native to North America, it has become a favorite turf grass from Maine to California, unsuitable only in the warm-season grass climates of the Southeast U.S. This long-lived perennial grass is a favorite for recreational areas as well as home lawns.
Kentucky bluegrass owes its name to the state, but the first seeds were possibly brought to the Americas by European settlers. Bluegrass is native to Asia and the mountains of northwest Africa as well as to Europe. Its vigorous crown and leaf blades and creeping growth pattern allowed it to naturalize rapidly. Kentucky named itself the "Bluegrass State" because the turf grass grows so well, particularly in the horse-raising northeast part of the state bordered by the Ohio River.
In addition to spreading by rhizome, some leaf blades turn downward and form new rhizomes, creating a compact turf that continually renews itself by forming new crowns. Kentucky bluegrass is slower-germinating than many lawn grasses, taking as long as a month to germinate. It makes up for its slow start, however, by continually establishing new crowns, ensuring that new generations will take over when old crowns die.
Kentucky bluegrass is widely used in lawns and athletic fields. Kentucky bluegrass performs well in full sun but needs companion grasses for lawns with mixed sun and shade. It is the chief grass in lawn mixtures containing perennial rye grass, bent grass or fescues, making it one of the most compatible types of lawn grasses. Bluegrass performs best when cut about 2 inches tall, making a mature stand of Kentucky bluegrass a thick, lush "barefoot" lawn.
Although Kentucky bluegrass is not a good grass for shady areas, its thick, gently-curved blades make it one of the most attractive lawn grasses, ensuring its popularity. Like other cool-season grasses, it has two periods of rapid growth; one in the spring and one in early fall. Root growth of Kentucky bluegrass peaks when the soil temperature is near 60 degrees F; because of the unpredictability of springtime warm-up, fall is the preferred time for seeding.
There over a hundred cultivars (varieties) of Kentucky bluegrass, many developed to tolerate close mowing or to flourish in warmer areas, adapting cool-season Kentucky bluegrass to transitional areas. With the development of Texas bluegrass, the range of bluegrasses extended to the U.S. Southwest. New Kentucky-Texas bluegrass hybrids will be developed for warm-season areas as well.