The snow and ice of winter can certainly be harmful to any of your plants, except for the hardiest among them. But since deciduous shrubs for the most part offer little of visual interest on the winter landscape, it makes no sense at all to expose them to the rigors of winter. Deciduous shrubs can be sheltered under a lean-to or similar structure.
For a full article on the subject, please consult Shrub Care -- Winterizing the Bushes in Your Garden.
Watering trees and shrubs properly in fall is another way to "winterize" them. In the next FAQ on evergreen shrubs, I explain why. And in the FAQ after that, we'll look at the proper regimen for watering in fall....

