Are your trees ready for winter? Last week I talked about the importance of winter watering but I want to touch on woody plant protection. Most of our herbaceous perennials die back to the ground and don’t need protection from small mammals. However, those plants that have a persistent above ground structure, tree and shrubs, might need some help.
Rabbits and voles are our main urban concern and some locations deer are a pest too. The damage is done when they gnaw on the bark to gain access to the wood. This damage disrupts the water conducting tissue and allows entry points for potential pathogens. If enough of the bark is removed the plant can be come girdled and will most likely die.
There are several over-the-counter products that may provide some limited management options to prevent damage. They work by irritating the nasal passageway or induce the fight or flight response. When food is limited they rarely provide any level of management. Some studies that were done in ideal conditions only had about a 17% efficacy. I don’t know about you, but I don’t think I want to risk replacing my plants.
Exclusion is the best and most effective way to prevent damage to our trees and shrubs. Yes you can make the argument that wire fencing around plants is not aesthetically pleasing – neither is a dead plant. Chicken wire is the most commonly used but the holes may be large enough to allow voles to slip through. Hardware cloth (contrary to its name) is a ¼” wire mesh that provides a better level of protection. Keep in mind it needs to go into the ground a few inches and be at least 18” tall. This will provide protection against voles and rabbits. Remember that snow makes an excellent platform for rabbits so the protection should extend the full 18” if not 24”.
A little bit of work on your part can make a big difference when it comes to the health of your landscape plants. Once the tree or shrub has been in the ground for about 5 years the bark should be thick enough to provide protection. There is no shame leaving the fencing up even longer if the rodent population is high.