Why do mice and rabbits cause damage to landscape plants in winter and how can this be prevented?
Especially during a period of extended snow cover, when their usual food sources are blanketed and therefore unavailable, these creatures seek out alternatives such as the bark of trees and shrubs. When partial girdling (cutting through the bark in a belt-like pattern) occurs due to this nibbling, insects and pathogens can gain easy access and weaken plants. If trunks and stems become completely girdled, the plants will die because water and nutrients no longer have a pathway from root to leaves.
In order to prevent this kind of injury, wrap the trunks and stems of susceptible plants with plastic covers or hardware cloths. Alternatively, rodent repellents can be sprayed onto the trunks and stems. Be sure to reapply in midwinter, during a time of warm temperatures.
Courtesy of the NYBG Plant Information Service