Mums are one of the most popular blooming plants for fall color in Nebraska. The most widely planted mum, the fall garden mum- Chrysanthemum x morifolium, recently underwent a name change so might also be listed as Dendranthemum x grandiflorum in many gardening books or magazines.
Mums are classified by flower shape, and are available in a wide range of colors including white, yellow, orange, bronze, red, purple and pink. Some of the most common types include daisy, anemone, pompon, cushion and button mums.Daisy mums have daisy-like flowers with 1-5 rows of long petals radiating from a flat, central, yellow "eye". Anemone mums are similar to daisy mums, but have a rounded crest of deeper colored, short petals in the center instead of a central "eye". Pompon mums have stiff, almost globular double flowers with no central daisy-like eye, on plants less than 18 inches tall.Cushion mums have double flowers on rounded plants usually two feet tall or shorter. Button mums have small double flowers on plants less than 18 inches tall.
Mums vary widely in cold hardiness. Floral mums, sold by grocery stores and florists year round, may not survive Nebraska winters, and if they do they may not bloom before a hard frost occurs. Visiting garden centers, parks and gardens in your area will give good idea of the cultivar selection available.
Chrysanthemums are adaptable to many soils types, but the soil must be well-drained due to their relatively shallow root systems. In poorly drained soils, soil-borne diseases may injure plants during wet summer periods resulting in root rots, while winter injury is likely if water stands around the crowns of plants during winter thaws. After planting, any depressions around your plants that might collect water should be leveled.
Plant mums in a full sun location, and place them 15-24 inches apart.When planting mums in the fall, allow at least six weeks of good growing weather for them to establish their root system before winter.Otherwise plants may be prone to winter injury.
Plants should be spaced 15 to 24 inches apart, and are most showy when planted in masses or small groupings. Place the plant's root ball slightly below ground level and gently firm the soil.After planting, water thoroughly to settle the soil around the plant.Thereafter, water the plants well once a week while they are still growing.More frequent watering may be required on sandy soils.Once the ground has cooled, in late November or early December, place a 2-3 inch layer of coarse mulch on the soil beneath the plants.
Plants grown in shade or semi-shady locations tend to grow taller or become leggy, have weaker stems and smaller flowers, and bloom later in the fall. Mums can be planted from container plants, cuttings or division. Larger plants or divisions can be planted anytime from early spring to early fall.
"Pinching" or removing the top ½ to one inch of each strong terminal shoot helps to develop a well-branched, vigorous, well-shaped plant. Pinching should be done 2 or three times, starting when plants are five to six inches high and ending around July 4th.
Problems commonly found with mums include winter injury if non-hardy varieties are grown or if plants desiccate (dry out) during the winter.Plants grown in shade or semi-shady locations tend to grow taller (be leggy), have weaker stems and smaller flowers, and fewer blooms.Late flowering of mums may be caused by using an inappropriate cultivar, insufficient sunlight, excess fertilizer, too much or too little water and late pinching. Root competition from nearby trees, unusually hot weather in August, or insect and/or disease injury also may delay flowering.