Don't divide mums in the fall

Q. I have hardy mum that blooms in the late summer and early fall. It is OK to divide them once they have finished blooming in the fall?

A. Don't be tempted to divide your mums in the fall. They respond best to being split in the spring, just as they're starting to grow. After the last spring frost when shoots are 1 to 3 inches tall, dig them up and carefully pull or cut them apart. Discard half-dead or overly woody parts, and plant only the healthy divisions.

It is a good practice to divide mums at least every two to three years in order to rejuvenate them and promote maximum flowering. Mums can withstand very cool temperatures and even light frosts. The first hard frost usually marks the end of the season for hardy mums. Once the plants are dormant, remove the tops, clean up old leaves and debris and re-mulch the area. New shoots will appear early the following spring.

Q. Why are my Mugo pines shedding needles. They've been healthy all these years and I see no signs of insects?

A. As fall arrives and nights become cooler, some needle loss on evergreens is normal. The needles in the interior of the shrub turn yellow and then drop off.

The amount of needles lost varies from year to year, depending on the past summer's weather. The needle loss may be more pronounced on newly planted or transplanted evergreens.

Ÿ Provided by Mary Boldan, Mary Moisand and Donna Siemro, University of Illinois Extension Master Gardeners. Send questions to Ask a Master Gardener, c/o Friendship Park Conservatory, 395 W. Algonquin Road, Des Plaines, IL 60016, (847) 298-3502 or via e-mail to cookcountymg.com@gmail.com.