When cold temperatures and winter weather, such as snow, sleet, wind and ice set in, it's easier to stay inside when you know your shrubs are safe and sound. Winter sun, wind, and freezing temperatures can affect plants, resulting in sunscald, desiccation of evergreen foliage, damage, or even killing of branches and roots.
While we might want to hibernate and think all creatures are doing the same while a fluffy white blanket of snow covers the ground, the reality is that deer and small animals, such as rabbits and rodents, are foraging for food. Plants in your landscape are likely part of their winter smorgasbord as they feed on twigs, bark, flower buds, and foliage. Here's how to keep your shrubs safe until spring.
Protect plants from animals using hardware cloth with a 1/4-inch mesh. Make cylinders to place around vulnerable plants, such as burning bush, blueberry, barberry, and shrub roses. Place around the shrub stem and push the lower edges of the cylinder into the ground to form a barrier.
Repellents are another option. Repeat applications are often necessary, particularly after heavy precipitation.
Newly planted shrubs are just as susceptible to sunscald as young trees. The chance for damage increases if they were pruned in the fall, exposing trunk tissue. Consider wrapping the trunk with a protective material, such as burlap or light-color corrugated paper. The key is to keep the bark temperature from extremes of cooling and heating. Established trees and shrubs won't need this protective wrapping, unless they have thin bark.
Evergreen broad-leaved shrubs and conifers are threatened by cold temperatures that can result in desiccation or browning of foliage. When temperatures are cold and the sun warms the leaves or needles, transpiration pulls water away. If the ground is frozen, the roots can't take up more water and the leaves dry out and turn brown (known as desiccation). Make sure the plants are well-watered in the late fall. Watering on warm days through the winter also can be helpful in warmer climates, where the ground isn't frozen.
Arborvitae and yews are some of the most susceptible shrubs to desiccation and winter burn. Younger, smaller plants can be protected by propping pine boughs -- one way to recycle your Christmas tree branches -- over the plants to act as a windbreak. This also helps catch snow, which acts as insulation. Low evergreens that are covered with snow are better protected and able to withstand wintry temperatures than those left to weather the winter sun and wind.
Products known as antidesiccants are touted as protecting foliage from drying out. Research has shown mixed results with these products, but some horticulturists think they are beneficial in preventing winter damage and recommend their use.
Burlap, canvas, or other landscape fabric can serve as a wind barrier. Not only are such barriers helpful to protect against salt damage, they can lessen wind damage and sun heating. Drive wooden stakes into the ground, then staple burlap to the stakes to form a wind barrier. Make sure they are placed on the wind-facing and south sides of plants. Plants with southern exposure are at greater risk due to higher temperatures from the sun, followed by extremely cold temperatures at night. Avoid plastic wraps around plants; they can heat up to the point of cooking the plant.
Mulching is a good practice any time, but it's particularly useful in helping plants weather winter extremes. Cover the root zone with 4–6 inches of mulch, which helps reduce fluctuation in soil temperatures and protects the roots. Avoid piling mulch directly against tree trunks and shrub stems, which increases the chances that rodents living in the mulch will feed on the shrub bark. Maintain roughly a 1-foot area around the base of a shrub that is free of mulch.
It can be tempting to prune any foliage or branches that have turned brown during the winter, but it's best to wait until new growth starts in the spring to more accurately determine damage. Though branches might look dead, they might bounce back.
If ice accumulates on shrubs, consider propping up branches to prevent breakage. Avoid beating the ice off trees or shrubs, which can cause limbs to break.
Of course, one of the best ways to increase your shrubs' chances of surviving a cold winter is to select plants that are suited to your climate. When selecting shrubs, trees, and other plants, check your hardiness zone and other required growing conditions to get the best possible plant for your location.