Hardy mum winter survival care tips
I had saved my hardy chrysanthemums in their original plastic pots and put the potted plants into the ground to over-winter. Now, I want to remove the plants from the plastic pots and transplant directly into the soil. When is the best time to do this?
Not many of the “hardy” potted mums bought in autumn in zone 4 will survive the winter. Even though they are called hardy mums, their hardiness can vary. Cold winters and poor draining soil are some of the factors that have an affect on their survival. In addition, when growing mums for the market, growers pay more attention to color, shape and abundance of flowers than to cold hardiness. The result is a beautiful plant with a root system that cannot support it.
When buying mums make sure they are hardy cultivars that fit your climate. In northern climates early blooming mums are more suitable. In zone 6-7 mid-season mums are better. Choose plants with buds that are just starting to open and show color.
By the time your potted mum hits the market, the plants are usually pot bound and full of roots. They will have a tendency to dry out much faster and need to be monitored every day for watering. If allowed to dry out, the lifespan is reduced.
Planting in the fall, doesn’t always work because there may not be enough time to develop a good root system, so for any chance of success plant in early fall or 6 weeks before the first frost. Plant your mums in an area with good winter drainage.
Best time to plant hardy mums is in the spring. In your case, try transplanting in the spring, when the soil is workable; if any viable roots wintered over, you should see some green shoots emerge when the weather warms up. Otherwise, buy hardy mum plants in the spring and see how big they get by autumn.
To help hardy mums survive the winter outdoors cut them back down to 6″ after they are done blooming leaving some of the stems to trap winter snow for insulation. Also, mulch your mums after a hard freeze with several inches of straw, pine needles or evergreens, the added insulation will protect the root system. Avoid using leaves as they tend to mat down and add little insulation.
Save your mums
Too late to plant outdoors? Keep your mums through the winter and plant them in the spring. Bring your mums inside before a hard freeze. Leave the plant in the pot and don’t trim it. Store your mum in a cool spot such as a garage or a shed. Water occasionally to keep the soil from drying out completely. Check on them periodically during the dormant winter season. In spring, when new growth emerges at the base of the plant, trim the dead stems and plant in the garden.