Ask a Master Gardener: Fall-planted mums considered annuals

Q. Why do mums that I plant in the fall fail to survive our winters?

A. The difficulty you are experiencing is because the plants have spent the summer growing in containers and have a compact root ball. While the plants can be transplanted into the soil without setback, there is not enough time for the roots to spread out into the surrounding soil.

As a result, winter freezing, heaving and drying often lead to the plant's death. That's why mums planted in the fall are considered annual, used for seasonal spots of color.

Your best chance with a potted mum purchased in the fall is to plant it in the ground, mulch and water it well, and cut it back to 3 inches after the blooms are spent. Once the ground freezes, cover with evergreen branches.

To help increase the chance that plants get rooted, slightly loosen up the root system by cutting down the sides of the root ball, thus increasing the plants ability to grow out into the surrounding soil.

Next year, you may wish to add chrysanthemums to your garden in the spring, so they have more time to establish.

Q. Last fall I put several inches of mulched leaves on my garden to add nutrients to the soil. In the spring the layer of mulch kept the soil from drying and it was late spring before I could dig the garden. Is there a better way to use the mulch in the fall?

A. Your idea to replenish soil nutrients with mulched leaves is good. Try digging your garden in the fall by doing the following:

Thoroughly remove all plant debris; it might be infected with fungus due to our wet summer.

Add 2-4 inches of disease-free mulched leaves onto the garden.

On a nice day in November or December, dig the garden mixing the leaves into the soil, breaking up only the large clumps of soil.

The winter freeze/thaw cycles will help break-up the clumps of soil into finer particles. Likewise, by digging in the fall you are exposing buried nuisance insect egg casings to the hard freeze. When the soil dries/warms in the spring, you should be able to rake it into fine till without strenuous digging.

• Provided by Mary Boldan. Master Gardener Answer Desk, Friendship Park Conservatory, Des Plaines, open 9 a.m. to noon on Monday, Wednesday, Friday and Saturday. Call (847) 298-3502 or email Cookcountymg.com@gmail.com.