Chrysanthemums, often simply called mums, are the undisputed queens of the fall garden. Their vibrant blooms provide essential color when many other plants are winding down for the season. To ensure these cherished perennials return year after year with a spectacular show, winterizing mums is a crucial step. This process protects the delicate crown and roots from freezing temperatures, ensuring a healthy and vigorous resurgence in the spring.
Understanding the Mums in Your Garden
The first step to successful winter care is identifying the type of mum you have. Garden mums purchased from nurseries are typically hardy perennials suited for USDA zones 5 through 9. These varieties are bred to survive cold temperatures. However, it is vital to confirm this specific hardiness, as florist mums sold for indoor arrangements are often treated as annuals and will not withstand the winter outdoors. Look for healthy, established plants that have already flowered; they are much more likely to survive the cold than newly planted specimens.
Timing Your Preparation
Knowing when to prepare your mums is just as important as the steps themselves. The ideal time to begin winterizing is after the first light frost has blackened the foliage but before the ground freezes solid. This usually occurs in late October or early November, depending on your climate. Acting during this window allows the plant to transfer energy from the stems to the crown and roots, building natural antifreeze compounds that protect it throughout the winter.
Pruning for Health
Once you have determined the right time, pruning becomes the next critical action. In the early stages of winter preparation, cut the stems down to approximately 4 to 6 inches above the soil line. This might seem drastic, but it serves several purposes. It removes diseased or insect-ridden material and prevents the stems from lying flat on the ground, where they could trap moisture and cause the crown to rot. The remaining stub provides a clear marker for where the plant is located once the snow falls.
Insulating the Crown
After pruning, the focus shifts to protecting the base of the plant. The crown, where the stems meet the roots, is the most vulnerable part of the mum to freezing. To shield it, apply a layer of mulch around the base. Use organic materials such as straw, shredded leaves, or bark mulch. Apply a layer that is approximately 4 to 6 inches deep, ensuring it covers the crown completely without burying the lower stems. This insulation regulates soil temperature and prevents damaging freeze-thaw cycles.
Watering and Drainage Considerations
While mums are dormant, they still require proper moisture management. Before the ground freezes, water the plants deeply if the autumn weather has been dry. This ensures the roots have ample moisture to sustain them through the cold months. Furthermore, verify that the planting site has excellent drainage. Mums detest "wet feet," and soil that remains waterlogged will lead to root rot. If your garden tends to pool water, consider transplanting the mums to a raised area or amending the soil with sand or gravel to improve drainage.
Pot Care and Transplanting
For gardeners growing mums in containers, winter care requires a slightly different approach. Terra cotta pots are particularly susceptible to cracking in freezing temperatures. Move potted mums to a sheltered location, such as an unheated garage or against a sheltered wall. Water the plants sparingly throughout the winter, keeping the soil just barely moist. If you wish to plant container mums directly into the ground, dig the hole slightly deeper and wider than the root ball to ease the transition and provide better insulation for the roots.
