Winter is a challenging time for trees and shrubs. Animals, wet snow, drying winds, sunscald, and deicing salts can damage trees and shrubs in the home landscape. Fortunately, steps can be taken to minimize damage to trees and shrubs in winter.
Animal Damage | Heavy Snow | Desiccation Injury | Sunscald | Deicing Salts | More Information
Animal Damage Over Winter
Rabbits
The most effective way to prevent rabbit damage to trees and shrubs in the home landscape is to place chicken wire or hardware cloth fencing around vulnerable plants. To adequately protect plants, the fencing material needs to be high enough that rabbits won’t be able to climb or reach over the fence after a heavy snow. In most cases, a fence that stands 24 to 36 inches tall should be sufficient. To prevent rabbits from crawling underneath the fencing, pin the fencing to the soil with U-shaped anchor pins.
Small trees can also be protected by placing white corrugated or spiral tree guards around their trunks. After heavy snow, check protected plants to make sure rabbits aren’t able to reach or climb over the fencing or tree guards. If necessary, remove some of the snow to keep rabbits from reaching the trees or shrubs.
Damage may also be reduced by removing brush, junk piles, and other places where rabbits live and hide. Trapping and repellents are other management options.
Some plants are more susceptible to damage by rabbits. Protection efforts for these plants should be prioritized. Learn more about plants prone to rabbit damage in this article: Susceptibility of Plants to Rabbit Damage.
Deer
Deer may feed on trees and shrubs during winter and severely damage or destroy plants. Damage is most likely to occur when food is scarce during prolonged periods of snow cover. Deer often feed on the foliage on the lower branches of arborvitae, pines, and other evergreens but also on other plants, especially when food is scarce. Prevention is key to managing this damage.
Exclusion is the most effective way to prevent deer damage. Tubes, wraps, wire fencing, and wire cylinders can be placed seasonally around individual trees and shrubs to physically exclude and prevent deer from browsing. When placed early in the fall, they are also often effective at preventing damage from antler rubbing. Guards, tubes, and cylinders are not permanent structures and need to be removed in spring. They are most effective on smaller, younger plants that are more susceptible to significant damage from deer feeding. These structures should be at least six feet tall. Wire cylinders can be shorter for smaller plants if they are closed on top.
Deer feed on a wide range of plants, but they do have their favorites! Some plants are more susceptible to damage by deer than others. Protection efforts for these plants should be prioritized. Learn more about plants prone to deer damage in this article: Susceptibility of Plants to Deer Damage
More Information on Wildlife Damage
How to Protect Trees and Shrubs from Animal Damage Over Winter
Damage from Heavy, Wet Snow
The weight of heavy, wet snow can cause considerable damage to small trees and shrubs. When heavy, wet snow accumulates on small trees and shrubs, gently shake the snow from their branches or carefully brush off the snow with a broom using an upward motion so as not to put more downward stress on the branches. Don’t throw heavy, wet snow onto small trees or shrubs when clearing driveways and sidewalks. Also, avoid dumping snow onto small trees and shrubs when raking snow from rooftops.
To prevent the weight of heavy, wet snow from damaging arborvitae and other multi-stemmed evergreens, wrap the plants with twine or rope in the fall. Promptly remove the support in the spring.
Learn more in this article: How to Prevent Ice and Snow Damage on Trees and Shrubs
Desiccation Injury
Narrow and broadleaf evergreens lose considerable amounts of moisture through their needles or leaves during winter. Water loss is mainly due to strong winds and the bright winter sun. However, once the ground freezes, plant roots can no longer absorb water. The water loss from drought-stressed plants during the winter months may be sufficient to cause the needles/leaves to turn brown and die. This type of damage is referred to as desiccation injury or winter burn. Evergreens most susceptible to desiccation injury include boxwoods, rhododendrons, arborvitae, and yews. Pines, spruces, and firs are also susceptible to winter desiccation for several years after planting.
To prevent desiccation injury, deeply water susceptible evergreens during dry periods in the fall. Water regularly until the ground freezes in winter.
Moisture loss can be reduced by erecting a shield or screen to deflect drying winds or shade plants in winter. A simple screen can be constructed with wooden posts, woven wire fencing, and burlap. The wire fencing supports the burlap and, if placed all the way around the plant, can double as animal protection. Do not wrap the burlap around the plant like a blanket. Instead, set the screen at least 6 inches from the plant's foliage.
Applications of an anti-desiccant to susceptible evergreens may also be helpful.
Sunscald Injury
Sunscald injury may occur on the bark of trees. It is characterized by an elongated, sunken, dried, or cracked area of dead bark, usually on the southwest side of a tree. The precise cause of sunscald is not well understood. It is typically attributed to temperature fluctuations. On cold days, the sun can warm the bark to the point where that area unfreezes. When the sun sets or is shaded by clouds, the active tissue refreezes and dies. Young trees, newly planted trees, and trees with thin bark are most susceptible to sunscald.
Trunks can be wrapped in the fall with tree wrap or plastic tree guards in an attempt to prevent sunscald. Remove the protective covering in the spring. The most reliable ways to reduce the incidence of sunscald is to leave lower branches on trees for as long as possible, avoid unnecessary wounding of the trunk, and prevent drought stress by properly watering young trees for the first two to five years.
Damage from Deicing Salts
Prudent use of deicing salts by homeowners can minimize damage to landscape plants. Before applying salt, wait until precipitation ends and remove as much ice and snow as possible. Use deicing salts at rates sufficient to loosen ice and snow from driveways and sidewalks, then remove the loosened ice and snow with a shovel. (Deicing salts need to be applied at much higher rates to completely melt ice and snow.) Mix salt with abrasive materials, such as sand or kitty litter. Avoid piling salt-laden snow and ice around trees and shrubs.
While the amount of salt applied to major roadways cannot be controlled, steps can be taken to minimize damage. As soon as the ground thaws in early spring, heavily water areas where salt accumulates over winter. A thorough soaking should help flush the salt from the root zones of plants. If possible, alter the drainage pattern so winter run-off drains away from ornamental plants.
More information can be found in this article: Using Deicing Salts in the Home Landscape