How to get fall garden mums through our winters

By Eric Barrett

OSU Extension educator

As soon as September arrives, the mum craze begins. The chrysanthemum is the highlight of the garden this time of year.

Many gardeners are frustrated with mums because few tend to survive the winter in our area. Why? Many changes have happened in the cultivar selection of mums to get better colors and better plants. And many gardeners are planting later and later into the season.

We can fix this. It’s not a guarantee — but you can get more of your mums through the winter with a little TLC.

When you purchase mums, be sure they are a garden mum and not a florist or pot mum. Garden mums are supposed to make it through the winter in our area if planted and cared for properly. All the mums at your local landscaper or farm market should be garden mums — but be sure to ask before you buy and read the label for zone/temperature information.

The best thing any gardener can do is plant them as early as possible. For gardeners who plant after Labor Day, here are some tips to help make them hardy:

Besides needing full sunlight, the fine, shallow roots of mums cannot compete with the roots of trees and shrubs. Wind protection, ample water, well-drained soil and proper fertilization are also key.

Work the soil well and be extra sure the area is well-drained because mums tend to get root diseases. Add compost or peat to the soil to be sure water goes away from the roots. Do not fertilize until you see them come back in May. Fertilizing in fall delays the plant’s winter hardiness preparation.

Normal spacing is about 18-24 inches, but as little as 12 inches is acceptable. Remember, if they survive they’ll grow bigger next season.

Rough-up the rootball, as most are pot-bound. Don’t be afraid to tear up the roots a little. Do not mulch until after the first hard frost.

Later-planted mums should be watered nearly every day. Do not let them wilt, but don’t let them sit in water. This will help the roots become acclimated to the surrounding soil.

Once the flowers have been blackened by late autumn frosts, apply a 2-inch layer of mulch around the plant. Cut the mum back, leaving 2-3 inches of growth above the mulch to help trap snow for needed moisture during winter.

For more information, go to: http://go.osu.edu/fallmums.