How to Protect Tree Bark and Evergreens in Winter

An evergreen, as its name suggests, is a plant that remains green throughout the year, unlike deciduous trees that shed their leaves in the fall. Common evergreen plants and trees include holly, live oak, pine, hemlock, cypress and spruce.

There are many reasons to plant evergreens around your property. Evergreens are more drought-tolerant than deciduous trees. They can add different sizes, shapes, colors and textures to your landscaping. And since they don't drop their leaves in the fall, they're a lot easier to maintain, too. Additionally, evergreens make great hedges, windbreaks and year-round privacy screens.

While evergreens will stay green throughout the winter, often they turn brown, lose limbs and even die in the spring. To the untrained eye, it may appear that the transition from winter to warmer weather killed the plant. However, in most cases, the damage actually occurred during the winter months.

Winter burn, or desiccation, happens when the evergreen loses more water than it takes in. You’ll see the damage in spring when sections of the plant are brown or rust-colored. Although plants often recover from this, they're unsightly and may lose branches from the ordeal. Winter burn can affect both broadleaf and needled evergreens.

Young trees and those with smooth, thin bark, such as aspen, birch and beech, are also prone to two more problems in winter: animal browsing and frost cracking.

Animal Browsing: Small animals, such as field mice and rabbits, will gnaw at tree bark when other food is hard to find in winter. These wounds offer an entry point for insects and diseases. If the gnawing goes around most of the trunk, the tree can die, which is why tree wraps offer excellent protection for trees during the cold weather months.

Frost Cracking: Also known as southwest injury because it's most likely to occur on the southwest side of a tree, frost cracking occurs on warm winter days when the sap underneath the thin, sunbaked bark warms up, then refreezes as temperatures suddenly drop at night. This causes ugly cracking, which can allow insects and diseases to enter. Trees with thick bark aren't affected.

Water deeply, soaking the root area, just before the ground freezes for the winter. Water below the surface of the ground is harder to freeze, so the deeper the water penetrates, the better the chance it has of remaining in liquid form for the roots to draw in.

Mulch around the base of your tree. Whether you use wood chips, bark, pine needles or another form of mulch, the goal is to help insulate the roots against the cold. Refrain from putting mulch directly against the trunk of the tree.

Wrapping the branches in netting or burlap will reduce wind flow around the tree, conserving water. It also protects the branches against damage from heavy snow. Follow the natural shape of your tree, taking care not to wrap it too tightly. If you use burlap, make sure to leave a hole at the top of the wrap to let the sun in.

If or when you brush snow off the branches, leave it around the roots. Snow is a great insulator and will help protect your roots against the colder air.

Avoid using de-icing salt near evergreens. If you must use it, don’t throw salt-contaminated snow near evergreens. Flush the ground beneath plants in the spring.

Want to protect your trees against animal browsing and frost cracking? Protecting the trunk with tree wraps is the best way. Tree wraps can be pulled taut against the trunks of both small and large trees, which means there are no gaps in which insects can hide, unlike plastic spiral tree guards, which don't offer as much tree trunk protection.

Applying tree wraps is easy. Starting one inch below the ground, wrap the paper tightly around the tree, overlapping each layer of paper by about half the width of the wrap, then fasten the ends of the wrap with duct tape. Be sure to remove the wrap in the spring to allow for renewed growth.

You can also minimize animal browsing with a rigid wire frame extending as far as the branches. As an alternative, you can spray the plants with animal repellent.