Chrysanthemums, commonly known as mums, signal the transition to cooler weather with their bursts of autumnal color. These flowering plants are a staple of fall landscaping, providing vibrant hues when many other garden plants are fading. Preparing them for winter requires specific, timely care focused on their immediate needs and long-term survival.
Essential Care While Mums Are Blooming
Mums require consistent moisture during their blooming period. The soil should be kept evenly moist but never saturated, which would risk root rot. Watering at the base of the plant, rather than overhead, helps to prevent fungal diseases like powdery mildew from developing on the foliage.
These flowers thrive best when they receive a minimum of six hours of direct sunlight each day. Adequate light exposure stimulates and sustains the intense flower production that gives mums their signature mounded appearance. Placing them in a location that receives full morning sun is often ideal, as it helps dry any overnight dew from the leaves.
To prolong the visual appeal of the plant, removing spent or faded blooms is recommended. This process, known as deadheading, redirects the plant’s energy away from seed production and toward developing any remaining flower buds. Deadheading keeps the plant looking tidy and prevents the development of botrytis blight on decaying flowers.
Determining If Your Mums Are Perennials
Understanding the specific type of chrysanthemum you have is the first step in deciding its fate after the fall display. Mums are broadly categorized into two groups: florist mums and garden mums. Florist or decorative mums are specifically bred for heavy flower coverage and are often treated as annuals with a shallow, underdeveloped root system.
Garden mums, also called hardy mums, are cultivated to develop a robust root structure capable of surviving winter dormancy. Garden mums are typically planted in the spring to establish themselves before winter, whereas florist mums are usually purchased in full bloom in the fall. If the plant was bought in a small, crowded pot with minimal visible foliage, it is likely a florist mum that will not survive a cold winter.
Hardy varieties, which are intended to return, often have a more open, branched growth habit with more visible foliage between the flowers. Florist mums are so densely packed with blooms that the leaves are barely visible. For the highest chance of perennial survival, choose plants labeled as “hardy” and plant them in the ground at least six weeks before the first anticipated hard frost.
Preparing Garden Mums for Winter Survival
Once the autumn blooms have completely faded and the foliage is killed by a hard frost, preparation for winter survival can begin. For perennial garden mums, it is best to leave the dead stems and foliage standing throughout the winter. This residual growth provides a natural layer of insulation, helping to protect the plant’s crown, where the stems meet the roots.
Applying a protective layer of mulch is the most important step for overwintering hardy mums. This mulching should be done after the ground has frozen solid, which prevents repeated freeze-thaw cycles that can heave the shallow roots out of the soil. A four- to six-inch layer of clean straw, pine needles, or shredded hardwood bark is suitable.
Avoid using heavy, unshredded leaves as mulch, as they can mat down and hold excessive moisture against the plant’s crown, leading to rot. The mulch serves to keep the ground consistently cold and frozen once winter sets in. The standing foliage and insulating mulch should remain in place until new growth emerges in the early spring, at which point the old stems can be cut back to a few inches above the ground.