Whether you’re growing mums in your garden or adding them to your containers, their colorful blooms are a dramatic component of autumn decor. When properly cared for, including regular watering and frequent deadheading, mums in containers can keep blooming for weeks or even months.
However, mums don’t last forever in containers, and once they start to look faded and tired, it’s probably best to get rid of them. You can try planting your mums in the garden, and let them become perennial, but they have a slightly better chance of making it through the winter if they’re smaller-sized plants (quart-size container or smaller) or you plant them a few weeks before the first frost.
Though there are some tricks for keeping your mums looking vibrant through the season, eventually, the blooms will start to slow down. Here are some obvious signs that your mums are starting to wind down and may be ready to discard.
Mums Stop Producing New Flowers
If you continue to deadhead your mums and remove spent flowers, they often continue to produce new buds for a while, keeping the show going. But once they stop producing new buds, it’s a sign they are starting to lose vitality. Once the buds slow down, continue to deadhead spent blooms.
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The Flowers Are Mostly Brown
If you’ve been regularly trimming off spent flowers, your mum will usually keep producing new ones within a couple of weeks. But if you’re noticing that the flowers are mostly brown and the overall colors are fading fast, it may be time to get rid of the plant.
Leaves Start to Look Less Vibrant
The leaves of chrysanthemums are either medium or dark green, with a leathery, somewhat glossy surface. If the leaves begin to look dull, this can be a sign that the mum is losing some vitality.
Along with deadheading faded flowers, you can also trim off any leaves that don’t look healthy. But once more of the leaves start to look dry or discolored, the mum is probably ready to be thrown away.
Mums Become Root-Bound in Containers
People use mums for fall decorations in different ways. Some buy them in baskets, some transplant them into their own containers, and some leave them in the nursery pots. The larger the mum plant, the more likely it may become root-bound in the container.
Keeping it well watered can help prevent this, as can moving it to a larger container with more soil. However, if the soil surface is hard and the roots are too crowded, the plant will stop being able to absorb moisture, and it may be a sign that the plant’s health is beyond improvement and may not be worth transferring over.
Leaves Get Powdery Mildew
Sometimes later in the season, the leaves of your potted chrysanthemums may start to accumulate some powdery mildew. The primary cause of this condition (which is sometimes seen on other garden plants like peonies or tall phlox) is a lack of air circulation.
Larger basket mums tend to have many flowers and leaves and the crowded conditions can make powdery mildew a bit more likely. Keeping the plant trimmed and deadheading spent blooms regularly can help prevent this. However, once your mum has been overtaken with powdery mildew, there’s not much to be done beyond trimming off the affected leaves as much as you can.
Mums Get Dry or Brittle
If your mums start to feel dry, or the leaves or flowers seem to break or fall off easily, they are reaching the end of their life cycle. Even if you water them regularly, mums that have become root-bound in their containers will not be able to absorb moisture very effectively.
Breaking up the root ball gently and planting in a larger container with fresh potting soil can help stave off this situation, and possibly prepare your mums for planting in the garden to come back as perennials, if you’re lucky.
