The cold weather has delayed work in the garden this year. Finish cutting back perennials and cleaning up garden debris as weather permits.
It is best to cut back perennials before they start growing to minimize any possible damage to the new growth. It can be hard to see new growth on ornamental grasses, so be sure to cut them back before consistent warm weather sets in later in the month.
If the weather warms up and the grasses are growing, cut them at a few inches above the ground to avoid the new shoots. Be careful of any bulbs that may have started growing.
• Begin uncovering hybrid roses around the middle of April (later than normal because of the cold weather) by carefully removing mulch from the base. A bamboo stake works well for this task.
Leave a small amount of mulch at the base for protection in case of a late hard freeze. Prune these roses back to live growth. You can identify live growth by the green stems, which in some years may leave only 1 to 2 inches of stem after you finish pruning.
I have noticed a lot of winter damage so far this spring.
• Install bare root plant materials as soon as possible after they arrive in the mail. Unpack plants and make sure the packing around the roots is moist. Store the plants in a cool place that will not freeze until they can be planted. It is a good idea to soak the roots of trees and shrubs in water for a short period of time before planting. Do not let the roots dry out.
Prune only broken branches and roots before planting. There is no need to prune to compensate for transplant shock.
• Most perennials are best divided in spring when they are showing a couple inches of growth. When dividing a plant, choose the strongest-looking parts of the plant and discard the rest.
A sharp, flat garden spade works best for this job. Plants that bloom in April and May can also be divided after they bloom.
• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.