Cold temperatures, heavy winds and ice can leave their mark on the landscape by winter’s end. Plants respond to damage in different ways, some species recovering without additional maintenance, others requiring a bit of TLC. Let’s take a look at how to manage winter damage by plant type.
Wind and ice often leave behind large broken limbs in trees. Before entering the landscape, assess safety from a distance. Look for limbs hanging in the tree canopy – these should be removed before working in the landscape and may require the assistance of a professional arborists.
Once the landscape is safe to enter, we can get to work on winter recovery efforts. Broken and damaged limbs need to be removed to allow trees to seal wounds and prevent secondary infection. Prune broken limbs back to a lateral branch using proper pruning techniques. Jagged tears in bark can be cut to a clean edge using a sharp knife.
Southwest injury or sunscald is another common type of winter damage. Alternate freezing and thawing cycles on the sunny southwest-facing side of the trunk leads to discoloration, cracks and sunken areas in the bark. This damage is common on young trees and species with thin bark such as maples and peaches. Prevention is the best technique for managing sunscald. The jagged edges of fresh wounds can be cut to a clean edge using a sharp knife to encourage healing.
Needled Evergreen Trees and Shrubs
Most needled evergreen trees and shrubs are more forgiving of winter extremes, though occasional damage may be observed. The most common type of damage is needle burn, in which the needles turn a brown or reddish-brown in color. Plants typically recover by producing a fresh flush of needles in spring. Wait until spring growth resumes before pruning any damaged limbs.
Ice storms can cause trees to bend over from the weight of ice. Most evergreens are limber and quickly recover with no damage. When no visible cracks or breaks in branches are present, give the plant time to recover before taking any action.
Broadleaf Evergreen Shrubs
Broadleaf evergreens can be damaged by fluctuations in temperature, prolonged dry periods, drying winds and bright sunshine. Winter burn, caused by water stress and drying winds, is most common, resulting in discoloration of needles, which appear reddish-brown, yellow, or gray-green. Winter burn affects the tips of branches, which can be removed with pruning shears or hand pruners. The plant will recover quickly.
Temperature fluctuations cause another type of damage. During warm periods, water moves through the plant stems. When temperatures drop below freezing, the water freezes and expands, splitting plant tissues. Cracks develop along stems and branches, or in extreme cases, entire branches can die-back. Dead and damaged tissues will not recover and need to be cut back to a lateral branch. Many evergreens are slow-growing and may take several years to fully recover.
Prune winter damage just before bud break in the spring to encourage new growth to cover pruning cuts. Wait to prune spring-flowering evergreens such as camellias and azaleas until plants finish flowering.
Deciduous shrubs may exhibit direct damage to limbs or die-back of shoot tips caused by cold temperatures. Damaged limbs should be removed as soon as possible to allow plants to seal wounds. Prune damaged limbs to a lateral branch or healthy outward-facing bud. Most shrubs respond well to pruning and can tolerate removal of up to one-third of total plant mass.
Identifying tip die-back can be more challenging. The easiest approach is to wait until shrubs resume growth in spring to determine how far back branches need to be pruned. Once bud break initiates, cut back shoot tips to a healthy, outward-facing bud, cutting at an angle one-quarter inch above the bud. Be patient, some plants are slow to start in spring. In extreme cases of cold-damage, shrubs may be “root-killed” meaning all above ground tissue has frozen back, but the root system remains alive. In these circumstances, it is appropriate to remove all dead stems to ground level and allow the plant to re-grow from the base.
With the exception of severe storms, much winter damage can be prevented by properly preparing plants for winter. Adequate irrigation and fertilization during the growing season promotes healthier trees entering the winter. A layer of mulch, windbreaks and bark protection for sensitive plants can reduce the most common types of winter plant injury.
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