You’ve cared for your young flowering crabapple all spring, summer, and fall. But failing to protect it in winter could be a fatal mistake for your tree or shrub. Rabbits, deer, mice, and other rodents are eyeing your woody shrubs and young trees, thinking of a midwinter meal. A few minutes now can save you the heartache and expense of replacing that tree later.

How deer and rodents damage trees

Rabbits, mice, voles, and other rodents (even porcupines) like to chew or strip off the tender bark on young trees and shrubs. They often don’t bother the woody plants in spring and summer when there are tastier and more appealing things to eat, but in winter, when all else is dead or gone, they’ll do damage enough to girdle (kill) a young tree in short order.

When the young bark is torn from the trees and eaten, the under layers that were protected are exposed, and the tree has trouble transporting water and nutrients up and down the stem. It’s those tender outer layers immediately under the trunk that move water and nutrients. When they are eaten, severed, or dried out, it’s called girdling. The roots are functioning, but the top of the tree can’t get water. The foliage is making carbohydrates, but they can’t transport them down to the roots. Girdling is basically choking the tree to death. 

Deer may strip bark, but more commonly they’ll just eat all the tender new growth, leaves, shoots, buds, twigs, and all. While we often think of deer as eating clover and grass, or our tulips, they are really browse eaters, and their digestive system is adapted to the twigs, buds, bark, and new growth. They won’t eat a one-inch tree trunk, but they will nip off all the tender ends of the branches. Bucks will also rub on young trees, shredding the bark and even breaking off smaller trees. That Cortland apple tree you planted and cared for three years ago is no match for a frustrated 8-point buck. He can demolish it in a matter of minutes and then move on, leaving you with a jagged stick and no apple tree.

Protecting woody shrubs and trees

There are a lot of semi-effective ideas for protecting plants and trees from critters. Some, like spraying noxious-smelling liquids, can work in the summer, but aren’t as effective in winter due to reapplication troubles in snow and freezing temperatures. Others, like sprinkling your pet’s hair around the base, or hanging soap from the branches, are more gardening myths than actual protection. 

To guard against sharp teeth stripping the bark from young trees and shrubs, there are really two options: tree tubes and wraps or wire cages. Regardless of the method, late fall is the perfect time to install protection and prevent winter damage.

Tree wrap tubes

Plastic tree wrap tubes come in many shapes and materials. Some are tubes, and some are wrapped around the tree in a spiral. Regardless, when installed correctly, they provide good trunk protection and are inexpensive. You can often find them at the garden centers and big box stores, and can probably protect all your young trees in less than an hour. The trouble is they don’t protect multi-stemmed shrubs or deter browsing deer from eating the lower branches. They also don’t stop a buck from trying to rub his antlers on your tree, which can not only tear up the bark but also break the tree off.

Tree wraps should be removed after the last spring frosts to allow air circulation and prevent problem insects from creating a home under the wrap. Rigid plastic tree tubes can be left year-round, but must eventually be removed as the tree grows. Once the tree has reached about 2 inches in diameter, the bark becomes less appealing to rodents. Of course, that buck deer may still give it a rub if they’re in the neighborhood.

Wire cages (better for shrubbery and deer)

Wire fence cages are more work, but offer a more effective way to protect young woody shrubs and trees. A plastic trunk wrap won’t work on a rose bush or dogwood. And while plastic tree wraps are great at keeping the trunk safe, they don’t do anything for branches that may be within a deer’s reach. Ask my lilac about that. 

Wire fencing cages are usually circular, although you could fashion one in nearly any shape. I have an oval cage that goes around three young hydrangeas. 

The two most common metal fencing products are chicken wire or welded wire fencing. Chicken wire fencing is less expensive and easier to cut, but it typically leaves a less professional-looking result. It works well for rabbits, but isn’t as rigid and a bit less effective (but still way better than nothing) for deer. However, I have many chicken wire cages around various shrubs and young trees, and with an extra fence post or two, they are working fine. 

Welded wire fencing is heavier-duty, rigid, and easy to make a good-looking circle with. It’s stout enough to keep the deer away, but smaller rabbits can get through. If you need a larger cage to protect the lower branches of an ornamental or fruit tree, welded wire is the best option.

A third option, called hardware cloth, is available with ½-inch or ¼-inch squares, which are small enough to deter mice and voles. It’s harder to work with and more expensive, but if it’s mice, not deer or rabbits, you are up against, it might be a better choice.

No matter the material, a wire cage needs to be tall enough to defeat the critter you are defending against. For rabbits, a 2-foot-tall cage is sufficient. Deer, of course, are taller. For protecting individual trees and shrubs, a four-foot-tall cage is normally sufficient. Make it wide enough that the lower branches aren’t hanging over. While deer can jump six or eight feet, they won’t jump into a small cage around a tree or shrub.

How to make a DIY wire cage

To make a circular wire cage, you’ll need some fencing, a few fence posts, a tape measure, leather or protective gloves, and a pair of wire-cutting pliers. Depending on the fencing, you may need a bit of wire to fasten it to the posts. The thicker the wire material, the heavier-duty pliers you’ll need. If you don’t have one, and the neighbor doesn’t either, you can buy one at the hardware store for about ten bucks. Don’t use your pruning shears! Wire-cutting pliers have hardened blades for cutting metal; your pruning shears do not.

Use your tape measure to visualize the diameter of the cage you need. For example, you may wish to provide a 2-foot-diameter cage around your young apple tree, or a 6-foot-diameter cage around your expensive Japanese maple, which is already 5 feet tall. After deciding on a diameter, it’s time for some math, but don’t worry. It’s pretty easy. 

The circumference of a circle is the diameter multiplied by pi. But for garden-level math, we can just say diameter times three and add a smidge. For example, for our 2-foot-diameter cage, we’ll multiply 2 feet by 3. The result, 6 feet, is how long a piece of fence we need. Keep in mind that a little extra is nice to make sure the edges overlap, and that the larger you get, the more those ignored decimals in pi add up. If you’re making a smaller cage, add half a foot. For large cages, add a whole foot of material. 

Cut the fencing as straight as you can. It’s easy with welded wire fence; harder to get straight with chicken wire. Mind the sharp edges of the cut fencing. 

Installation

For mice and other rodents, the cage should be buried an inch or two into the ground and secured tightly. While they may burrow deeper, it’s usually enough to keep them from mischief once the ground is frozen. The easy way is to form your cage around the tree, then use it to mark where to dig the shallow trench. A helper makes this task easier, but you can do it solo.

Hammer the fence posts into the ground at least a foot. No need to go super deep, but they should be firm and stay upright. Fasten the fencing to the posts at the bottom, the top, and at several points up the posts. How many depends on how tall your cage is. Zip ties also work, but get the ones rated for outdoor use so they won’t get brittle in UV light.

Hint: Leave the sharp edges of wire ties on the inside of the cage, not the outside, where you might brush against them and get scratched later. The same goes if you trim the long ends of zip ties.

Check on your tree wraps, tubes, or wire cages several times during the winter to ensure they haven’t shifted, come unwrapped, or been pushed around.