The winter survival rate for mums planted in late summer and fall is much lower because they do not have adequate time to establish in the landscape. Therefore, fall planted mums should be considered an annual in the garden and replanted every year. To ensure compact, bushy plants with tons of blooms, pinch mums several times in spring and early summer. Pinching requires removing the shoot tips forcing the plant to produce additional shoots along the stem. Stop pinching by July 4 since removal of shoot tips after this date can delay or prevent the formation of flowers.
Mums generally require regular fertilization and irrigation throughout the growing season.
Fertilization once a month through July with a complete water-soluble fertilizer should be sufficient. Continued fertilization late in the season can promote succulent growth that may not have sufficient time to acclimate for winter. Water chrysanthemums once a week during dry weather. Overwintering Strategies Probably one of the most confusing aspects to growing mums is the unexplained sudden death or loss of plants during the winter. There are several strategies that can aid in overwinter survival of garden mums.