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.
Preventing Animal Damage Over Winter
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 a 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 may feed on trees and shrubs during the winter months 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 feed 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 as long as they are closed on top.
Other tactics can be used to discourage or prevent deer from feeding on trees and shrubs over the winter. Learn more about preventing deer damage in this FAQ article: How can I prevent deer browsing and feeding during the winter months?
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: Resistance of Trees and Shrubs to Deer Damage
Preventing 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. When clearing driveways and sidewalks, don’t throw heavy, wet snow onto small trees or shrubs. 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 fall. Promptly remove the support in the spring.
Preventing Desiccation Injury
Narrow and broadleaf evergreens lose considerable amounts of moisture through their needles or leaves during the winter months. The loss of water is mainly due to strong winds and the bright winter sun. Once the ground freezes, however, plant roots are no longer able to absorb water. The loss of water 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 fall. Water on a regular basis 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 provides support for 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 foliage of the plant.
Applications of an anti-desiccant to susceptible evergreens may also be helpful.
Preventing 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. On cold days the sun can heat the bark to the point where that area breaks dormancy. When the sun sets or is shaded by clouds, the active tissue freezes 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 to prevent sunscald. Remove the protective covering in the spring.
Preventing Damage from Deicing Salts
Prudent use of deicing salts by homeowners can minimize damage to landscape plants. Before applying salt, wait until the precipitation has ended and remove as much of the 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.
Updated from an article that originally appeared in the November 13, 2017 issue of Horticulture and Home Pest News.