Pinch occasionally to maintain the shape. Even the so called 'hardy' mums may not consistently over-winter in Nebraska. Loose mulches such as leaves, if applied properly, may increase winter survival. Plants should be mulched late in the fall and the mulch removed early in the spring. Mulches applied and used improperly can suffocate new rhizomes as they emerge.
Chrysanthemums usually have few insect problems.
Aphids, leafhoppers, spider mites, grasshoppers and leafminers occasionally may injure plants. Correctly identify any insect before insecticides are applied. Small numbers of insects may not cause enough injury to warrant chemical control. Mums generally are not susceptible to diseases if they are vigorous and well cared for. Proper cultural practices help prevent diseases.