Chrysanthemums, often called mums, are popular garden additions that provide vibrant color late into the season. These flowering perennials require regular trimming to maintain their attractive mounded shape and ensure a continuous, healthy display of blooms. Removing dead or spent plant material is an important maintenance task that benefits the plant’s overall vigor and longevity. A consistent trimming schedule, including light seasonal maintenance and a heavier cutback for winter, promotes strong growth and maximizes the plant’s flowering potential.
Seasonal Trimming: Removing Spent Blooms
Seasonal trimming, known as deadheading, focuses on removing individual flowers as soon as they begin to fade during the active blooming period, typically from late summer into fall. This practice redirects the plant’s energy away from seed production and towards generating new buds and blooms. Allowing a flower to remain on the stem and form seeds shifts the plant’s hormonal signals, reducing the development of new flowers. By consistently removing these spent blooms, you encourage the plant to continue producing more flowers.
The technique for deadheading can be simple, often involving just pinching off the faded flower head. For larger or tougher stems, small, sharp snips or shears can be used to make a clean cut. The cut should be made just above the first set of healthy leaves or a visible side bud below the spent flower. Making the cut at this point encourages new growth to emerge from that node, which maintains the plant’s dense, rounded form and prevents unsightly brown stems.
If a large cluster of flowers has faded simultaneously, a light shearing of the top layer of growth can be performed instead of individual deadheading. This faster method removes the bulk of the spent material and allows sunlight to reach the dormant buds lower down on the stems. Regular deadheading, even once or twice a week, is far less overwhelming than waiting until all the blooms have faded and ensures that the plant’s energy is always focused on the next wave of color.
End-of-Season Cutback: Preparing for Winter
The end-of-season cutback is a structural pruning done late in the year to prepare the plant for dormancy. This heavier trim is usually performed after the foliage has turned brown or after the first hard frost has occurred. The goal of this cut is to remove all the withered, above-ground growth that will die back during the cold months.
Cutting the entire plant back significantly minimizes the risk of pests and diseases, such as powdery mildew, from overwintering in the dead foliage. The stems should be cut down to a height of 4 to 8 inches above the soil line. Leaving a short stubble of stems helps to mark the plant’s location before spring growth begins.
In colder climates, some gardeners choose to leave the dead stems standing through winter, as this material can provide natural insulation for the crown and roots. If you opt for this approach, the final cutback should be delayed until early spring, before new growth starts to emerge. Applying a layer of mulch around the base of the plant after the cutback helps further protect the root system against extreme winter temperature fluctuations.
Essential Tools and Hygiene
Trimming mums requires using sharp tools to ensure clean cuts that heal quickly and minimize stress on the plant. For seasonal deadheading, small bypass snips or household scissors are sufficient for clipping delicate flower heads. For the heavier end-of-season cutback, hand pruners or larger hedge shears are necessary to manage the thicker, woody stems.
Maintaining tool hygiene is a fundamental step in plant care, particularly with chrysanthemums, which are susceptible to fungal diseases. Before and after trimming, the cutting blades must be disinfected to prevent spreading pathogens. A simple and effective disinfectant is a solution of 70% isopropyl rubbing alcohol, which can be wiped or sprayed onto the blades.
Alternatively, a bleach solution mixed at a ratio of one part household bleach to nine parts water can be used for sterilization. After using a bleach solution, the tools should be rinsed with clean water and dried to prevent corrosion. All trimmed dead material should be promptly removed from the area, as leaving it on the ground near the plant can harbor pests and disease spores.