Rabbits and voles (field mice) are the primary animals that may gnaw on tender bark of trees and shrubs in winter. Putting up a barrier, such as poultrywire or hardware cloth, is the best defense. Put a fence around shrubs, and secure with a few stakes. Put a loose cylinder of hardware cloth around the trunk base of younger trees susceptible to vole or rabbit gnawing. Removing excess vegetation and debris near plants will also help reduce cover, especially for voles.
Repellents are also available to help protect plants from gnawing animals. Research studies have concluded results vary depending on location and even the specific year when using repellents. However, there are some important points to consider. Keep in mind repellents will reduce but not eliminate animal damage to plants. A good chickenwire barrier may eliminate rabbit damage to shrubs, but a good repellent may simply reduce the damage. So if some damage occurs, don’t blame the manufacturer, as damage may have been reduced but not eliminated. Remember results vary considerably in studies.
There are two types of repellents, contact and area. Contact repellents are applied directly to plants and repel by unpleasant taste for the animal. Some product examples include DeerAway, Ro-Pel, Miller Hot Sauce, and thiram (a fungicide). Area repellents are applied in the vicinity of plants and usually repel by smell. Examples include Hinder, dried blood, bar soap, and human hair.
Research studies show not every repellent works in every situation, but contact repellents are more effective than area repellents. Commercial products appear more effective than “home-made” remedies. If you’re planning to use a repellent this winter to protect shrubs and trees, read the labels thoroughly. Most need to be reapplied during the winter. Consider fencing or other barriers for more dependable protection – even though the initial costs are higher, remember they can be reused.