What can I do to help my mums survive the winter? 

Chrysanthemums are shallow-rooted plants. Repeated freezing and thawing of the soil during the winter months can heave plants out of the ground and cause severe damage or even death. 

Gardeners can increase the odds of their mums surviving the winter by applying mulch in the fall. Mulching helps eliminate the alternate freezing-thawing cycles that can heave plants out of the soil. Mulches should be applied in late fall, typically late November/early December in central Iowa. Do not cut back the plants prior to mulching. Simply cover plants with several inches of mulch. Suitable mulching materials include clean straw, pine needles and evergreen branches. Leaves are not good mulch as they tend to mat down and don’t provide adequate protection. 

My bittersweet vine doesn’t produce any fruit.  Why? 

American bittersweet (Celastrus scandens) is dioecious. Dioecious plants bear male and female flowers on separate plants. Gardeners need to plant at least one male and one female bittersweet vine to produce fruit. Unfortunately, most bittersweet plants sold at garden centers and nurseries aren’t labeled as to sex. As a result, several bittersweet vines should be planted to ensure getting at least one male and one female plant. For best fruiting, plant the bittersweet vines in full sun. 

How can I prevent rabbits from damaging trees and shrubs in my yard over winter? 

During the winter months, rabbits often gnaw on the bark of many woody plants. Heavy browsing can result in the complete girdling of small trees. Those trees that are girdled are essentially destroyed. Small trees with smooth, thin bark are most vulnerable to rabbit damage. Apple, pear, cherry, plum, crabapple, hawthorn, honey locust, willow and serviceberry are frequent targets of rabbits. On shrubs, rabbits may girdle large stems or clip-off small twigs at snow level. Frequently damaged shrubs include the winged euonymus or burning bush, flowering quince, chokeberry, fothergilla, barberry, cotoneaster, forsythia and dogwood. Roses and raspberries also are frequently damaged by rabbits. Rabbit damage is most severe when the ground is covered with snow for prolonged periods. 

The best way to prevent rabbit damage to young trees is to place cylinders of hardware cloth around the tree trunks. The hardware cloth cylinder should stand about 1 to 2 inches from the tree trunk and extend at least 12 inches above the anticipated snow line. The bottom 2 to 3 inches should be buried beneath the soil. Small shrubs, roses and raspberries can be protected with hardware cloth or chicken wire fencing. 

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