Pink, white, lavender, maroon and bronze are all different colors of fall mums. These flowers actually are chrysanthemums, but most growers just call them garden mums. They are traditional during autumn months, since they naturally flower at this time of the year. Trials at the University of Kentucky College of Agriculture's horticulture research farm evaluate many varieties of chrysanthemums for fall flowering."The type of flowering chrysanthemums sold in the fall are often called hardy mums, but all types are not reliably hardy in Kentucky," said Bob Anderson, UK Extension horticulture specialist.Many people use garden mums to decorate for fall and most greenhouses and garden stores have mums for sale. The production of garden mums for fall sales began months ago. Growers received cuttings of patented varieties in late May, June, or early July."Just over a million garden mums were grown in pots or planted in rows in a farm field this year in Kentucky," Anderson said. "The plants have been watered and fertilized all summer to produce the large plants that are now available."Plants are covered with flowers that will last four to six weeks. Mums need a garden location where they will receive at least six hours of full sunlight each day. During the warm and dry fall weather, they should be regularly watered. They like cool nighttime temperatures and their colors are brightest and last longest under cool conditions.As days shorten, chrysanthemums begin to flower. This means the plant has an internal control to tell it when Fall is on the way. The plants react to the decreased day length in late July and sets flower buds that will open in September before the killing frosts of October. Growers observed this phenomenon more than 75 years ago and now chrysanthemum growers can get mums to flower anytime of the year in greenhousesMost garden mums are garden perennials in northern states, but great variations in winter temperatures in Kentucky can kill garden mums in certain years."A few old fashioned varieties seem to be hardy in the state every year, but no one has made an effort to propagate and sell these older, nameless, traditional varieties," Anderson said.