Don't pile up mulch. If it's too deep, it can provide cover for mice and voles that tunnel through and chew on the bark of shrubs and young trees, according to Peter Linsner, who is in charge of controlling animal damage at The Morton Arboretum. Spread mulch in a wide, even layer just 2 to 3 inches deep, and make sure it stays a couple of inches clear of the stems or trunk.
Clear snow. Deep snow piled against plants also can provide cover for tunneling animals, so it's a good idea to clear it away from around the bases of especially vulnerable plants.
Protect young trees and shrubs. When they are small, their bark is tender and their twigs are tempting to rabbits and other animals. Rabbits are especially fond of certain species, including Japanese kerria, oakleaf hydrangea and fothergilla, Linsner says. The best way to protect a plant is by fencing it with a well-anchored cylinder of hardware cloth.
No plant is animal-proof. "There are plants that animals don't favor; if there's plenty of food around, they'll leave them alone," Linsner says. But if the winter is hard and food is scarce, rabbits and deer will be less picky. You can find many lists of rabbit-resistant or deer-resistant plants online. Most of them have a strong odor or a fuzzy or prickly texture.
Beth Botts is a staff writer at The Morton Arboretum in Lisle (mortonarb.org).