Chrysanthemums: perennials?

By Judy Bernard, Master Gardener

One of the early signs that summer is coming to a close is the proliferation of potted mums. These beautiful fall flowers come in a range of colours from white to yellow to burgundy and almost everything in between. They disappear when flowering is done, only for new ones to appear next year all potted up and blooming profusely again. Although they are perennial (zone 5-9), one doesn’t usually find them in the flower bed, but instead they are displayed in wonderful potted arrangements.

At the end of the season, rather than putting them in the compost, why not try planting them?

There are a few things one can do to try to help your mums survive the winter in the ground:

Choose plants whose buds haven’t started to open. Plant them in a larger pot with fresh potting soil for display purposes, then, at the end of the season plant them directly in the ground.
Mums need full sun 5-6 hours daily.
Mums need rich well drained soil, so add compost to the soil when planting.
After blooming is finished cut the plant back to about 10cm from the ground. (Or wait and do this in the spring )
Mums have shallow roots, so it’s important to mulch them well with several inches of mulch to keep the roots from heaving through the freeze thaw cycles of winter. If you see that they have heaved, just push them back into the ground.
They also need lots of water, so keep them well watered in the pots as well when you put them in the ground

If you’ve been successful and the mums survive the winter, the operative word here is “if” as they have been forced into the wonderful growth we see. So, if they survive:

As they are susceptible to mildew, they need plenty of air circulation, and morning sun to dry the dew from the leaves. Don’t plant them where they will be boxed in.
Once they have reached a height of 15cm pinch the new growth back to encourage side shoots and more fall flowering. This can be done a few times until mid to late June.
Keep the plants well-watered and fertilized with a 5-10-10 fertilizer.
Enjoy another burst of colour from these amazing plants the next fall.

You may also want to keep an eye out at the garden centres in the spring for perennial Chrysanthemums that you can grow in your garden. There are many beautiful cultivars in a wide range of colours and sizes that will keep your fall flower bed looking spectacular.