Chrysanthemum is also known as Dendranthema x grandiflora. Mums are considered a harbinger of the fall season. They come in lovely colors of yellow, red, orange, purple, bronze, pink and white. The origin of chrysanthemums is traced back 2,000 years to China. The chrysanthemum is also the national flower of Japan. In the United States, it has become an extremely popular fall flower. Many garden cultivars have been produced in the United States through hybridization of the chrysanthemum.
These lovely flowers come in several shapes and petal arrangements. Mums are classified by the shape of their flowers, and their petal arrangement. Purdue University lists the following classifications: single--daisy-like flowers; pompon--small globular; cushion or "azalea" mums--bushy plants; anemone--similar to single; decorative--incurved flowers; spoon--spoon-like petals; spider--long, tubular petals; and quill--straight, long petals.
Chrysanthemums need to be planted in well-drained, organically rich soil. They will require a site that receives full sun. Chrysanthemums also like slightly acidic soil (pH 6.5). The best time to plant chrysanthemums is in spring (mid-May). Plants should be spaced from 18 to 24 inches apart (dependent upon the expected size of the mum you are planting). Apply a slow release fertilizer after planting.
Plants will require regular watering. They can survive a short period of drought but are not drought tolerant. Chrysanthemums respond to a good soaking (depth of 5 to 6 inches). Direct the water at the soil--avoid getting the foliage wet. Do not water lightly and frequently. Light and frequent watering causes the plant to develop a shallow root system. According to Purdue University's Department of Horticulture, shallow root systems make the plant more susceptible to diseases such as: mildew, verticillium wilt and septoria leaf spot.
Pinching produces bushy and well-shaped chrysanthemums. Pinching is done by hand, using your thumb and forefinger. Pinch off or remove the end of the shoots--approximately 1/2 to 1 inch of the shoot. This is done early in the season (mid-June) when plants are approximately 6 inches in height. After the first pinching, the plants then grow lateral branches. When the lateral branches are 6 to 8 inches in length (mid-July), pinch these lateral branches back 1/2 to 1 inch.
Mums do not always come back the following year. In fact many gardeners consider them an annual instead of a perennial. If you want to try to keep them over winter, Ohio State University Extension suggests cutting off the tops of the plants once frost has killed the foliage, and then covering the plants with 3 to 4 inches of mulch.