Chrysanthemums (mums) provide vibrant color when many other plants are fading. Moving or planting mums in the fall is often necessary. The short answer is yes, but success depends on careful timing and follow-through. This requires understanding the plant’s shallow root system and the demands of establishing itself before winter arrives.
Optimal Timing for Fall Transplanting
The success of a fall mum transplant hinges on giving the plant enough time to establish its root system before the ground freezes. This requires a minimum of six weeks before the average date of your first hard frost. Planting later significantly reduces the likelihood of the mum surviving the winter.
Newly purchased mums, especially those in full bloom, often have a dense, root-bound structure that needs loosening before planting. Established garden mums experience less shock if moved while the soil is still warm enough to promote new root growth. The goal is to encourage fine feeder roots that anchor the plant and draw in moisture, a process that slows dramatically as temperatures drop.
Preparing the Plant and the New Site
Preparation should occur one to two days before moving the plant. Begin by thoroughly watering the mum in its current location. This ensures the root ball is hydrated and helps the soil cling together during the move, minimizing transplant shock.
For larger, established mums, prune the foliage back by about a third. This reduces the leaf surface area the roots must support, redirecting the plant’s energy toward root development.
Prepare the new planting site by digging a hole the same depth as the root ball but two to three times as wide. Mixing organic matter, such as compost, with the native soil improves drainage and aeration, which is beneficial for mums sensitive to overly wet conditions.
The Physical Transplant Process
The transplant process must prioritize the integrity of the root ball, as mums are shallow-rooted and easily damaged. When digging up an established plant, use a sharp spade to cut a wide circle around the plant, aiming to capture as much of the root system as possible. The root ball should extend at least 6 to 8 inches from the base of the stems.
Carefully lift the root ball with a shovel or spading fork and transport it to the new location. Before planting, gently tease apart any tightly matted or circling roots to encourage outward growth.
Set the plant so the top of the root ball is level with the surrounding soil surface or slightly higher; planting too deeply can lead to crown rot. Backfill the hole with the amended soil, lightly tamping it down to remove air pockets that could dry out the roots.
Essential Aftercare for Winter Survival
Immediately after transplanting, the mum requires deep watering to settle the soil around the roots. This initial watering is crucial for eliminating small air gaps and ensuring direct contact between the roots and soil particles. Maintain consistent moisture, avoiding saturation, until the ground freezes.
Once the ground has frozen, typically after the first hard frosts, apply a thick layer of protective mulch, such as straw or pine needles, around the plant’s base. This insulating layer, ideally three to four inches deep, keeps the soil temperature stable.
The mulch prevents the cycle of freezing and thawing, which causes frost heaving that can push the shallow root system out of the ground. Leaving the existing stems and foliage intact over the winter also provides additional insulation and protection for the crown of the plant.