Chrysanthemums, or mums, are the undisputed royalty of the fall garden. Their vibrant blooms provide a much-needed splash of color as the days grow shorter and the landscape prepares for dormancy. However, many gardeners view these beloved perennials with uncertainty when the frost arrives. Understanding how to keep mums over the winter is the difference between losing these cherished plants and enjoying their return the following season with vigor and abundant flowers.
Preparing Mums for the Cold Months
The groundwork for a successful winter is laid in the late summer and early fall. It is crucial to time your preparations correctly to align with the plant's natural growth cycle. You want to encourage robust growth before the cold sets in, while also ensuring the plant is not so flush with new growth that it becomes vulnerable to frost damage. This preparation phase is about building resilience.
Pruning and Pinching
As the season progresses, you will need to adjust your care routine significantly. In the early part of the season, pinching back the stems encourages a bushier plant with more flower buds. However, once the plant begins to bloom, you should cease pinching. In late fall, after the first hard frost has blackened the foliage, you should cut the entire plant back to about 4 to 6 inches above the ground. This cleanup removes diseased tissue and directs the plant's energy toward the roots, which is where the survival instinct lies.
The Critical Role of Location and Soil
Not all planting spots are created equal, and this is especially true for winter survival. Mums require excellent drainage; sitting in cold, waterlogged soil is a primary cause of root rot during the winter. If your garden tends to pool water, you must either amend the soil heavily with organic matter or consider planting the mums in raised containers that can be moved to a sheltered location.
Mulching for Insulation
Once the ground freezes, a layer of mulch acts as a thermal blanket for the root system. Apply a thick layer of straw, shredded bark, or leaf litter around the base of the plant. This insulation protects the roots from the damaging freeze-thaw cycles that can heave the plant out of the soil or cause root damage. Ensure the mulch is applied after the ground has frozen to prevent rodents from nesting in the warmth.
Watering and Moisture Management
While the frequency of watering decreases, it does not stop entirely. You must monitor the moisture levels in the soil throughout the winter, particularly during periods of warm spells or windy conditions. Evergreens and the ground itself can act like a sponge, pulling moisture away from the roots. If the soil becomes bone dry, the plant will desiccate and die, even if the roots are technically insulated.
Hydration Before the Freeze
In the days leading up to the first hard freeze, give your mums a deep watering. This ensures the soil is saturated going into the coldest period. A well-hydrated plant is better equipped to handle the stress of freezing temperatures. Remember to water during any extended dry periods in the winter, but avoid watering when the ground is covered in ice or snow.
Temperature and Wind Protection
The ambient temperature is only one factor; wind and sun exposure can be equally damaging. Winter winds can dry out the plant's tissues, while the warmth of direct sunlight on a sunny winter day can trick the plant into breaking dormancy. When the sun goes down and the temperature plummets, the new growth is often killed off. Protecting the plant from these elements is essential for maintaining consistent dormancy.
