Mum’s the Word
“Seal your lips and give no words but mum.”
- William Shakespeare, Henry VI
Gardeners tend to love mums—actually chrysanthemums—for their fall color, beauty, and variety of forms. Readers frequently ask, “Are mums annuals or perennials?” Well, if they don’t come back next year, they sure act like annuals.
If you were able to purchase mums early in the gardening season, the roots probably will develop well enough for the mums to successfully overwinter and to return next year. They will wait until just the right time to start flowering in your garden. This is because mums are “short day plants,” which means they set buds when night time is about ten hours long. That is why mums don’t flower earlier even if it is warmer, colder, wetter, or drier than usual. All mums don’t bloom at the same time, however, making autumn a wonderful time to enjoy flowers from early, mid, and late season.
All mum plants don’t look alike. You are perhaps most familiar with cushion and daisy-like mums, but there are also quill mums, spider mums, and anemone mums. Great fun!
Now, there is nothing wrong with using mums in your garden as annuals. Some gardeners don’t want to wait all gardening season long for a plant to bloom in the autumn. If planted in the spring, the plant will take up space that could be occupied by an annual that gives a longer season of bloom. Another reason is that mums have shallow roots, which means that their roots are closer to the soil surface and can heave out of the ground during the winter. Mums planted in the autumn have the disadvantage of having been forced into bloom in greenhouses, making them lovely autumn plants but plants that frequently develop even shallower root systems when planted in a garden.
You can mulch your mums, however, and also cover them with layers of leaves or compost, which not only serves as a winter mulch but also weighs them down, keeping them in the soil rather than on top of the soil exposing them to drying wind.
Plant them in well draining loose soil in full sun no matter the season. If mums are spring planted or returning again in the spring after being planted in the autumn (Good for you!) be sure to pinch the stems back about every two weeks until July 4th so the plants will not get floppy. They will reward you by producing a dense mat of flowers. If the autumn is dry, be sure to keep your mums well watered until the end of the season.