It’s COLD! Your first priorty should be to take care of yourself and be prepared for the cold-weather. I previously listed some ideas for ways to work and be outside in the cold. Trees can also be damaged by this unusually cold weather we are experiencing. Here are some common “winter ailments” that can cause problems for your trees and shrubs.
Low Temperature Injuries: All parts of a plant can be damaged by freezing temperatures, but the root systems of trees are often damaged without the homeowner knowing. During open winters (no snow cover), root damage may occur on plants during prolonged cold periods. Shallow rooted plants and container plantings are generally the most susceptible. Symptoms of root mortality usually are evident in late winter or spring. – as the plant “wakes up”. Foliage may turn brown, buds can die and the entire crown may wilt and die suddenly. Low temperatures can also kill above ground portions of plants. This injury generally affects non-native, marginally hardy plant material.
Desiccation of Plant Tissue – Also known as “Winter Drying”: Winter drying generally affects evergreens, usually broadleaf evergreens such as mountain laurel, rhododendron, azalea and holly. Taxus, arborvitae and Chamaecyparis also are commonly affected. This injury results from water loss during sunny days in winter when the soil is frozen. Water lost through foliage is not replaced from the frozen soil, and this results in drying of the foliage. The south and southwest portions of the plants are usually affected most severely because of their exposure to wind and sun. Plants in exposed, windy locations, recent transplants and plants with root damage from drought or disease also are prone to winter drying.
Stem Splitting – “Frost Cracks”: Frost cracks generally occur on young thin barked trees such as maple, sycamore, zelkova and linden. This injury generally results from a sudden drop in temperatures – a sunny daytime high to very low nighttime temperatures. This may cause sudden shrinkage of stem tissues or can freeze sap within the cells, resulting in a frost crack. This damage is evident as a vertical seam or crack that is most evident on the south-southwest portion of the trunk. Frost cracks can create hazardous conditions that lead to decay on certain species by exposing wood tissue to infection by decay organisms in the future.
Breakage from Snow and Ice Accumulation: Trees with poor growth structure, such as co-dominant (double) leaders, narrow branch attachments and heavy or long limbs are prone to breakage due to the added weight of ice and snow. Wood decay can also predispose branches and leaders to failure from ice loads. Evergreens that have a large surface area to “hold” snow are also prone to breakage. Foundation plants near the overhang of structures also tend to accumulate heavier snow and ice loads. Proper pruning can help prevent this type of injury – as can inspection of your plants after a heavy snowstorm
Animal Injuries: Deer browse can cause severe injury to foliage and twigs of landscape plants, especially in snowy winters. The lower stem and root collar of plants can be damaged and even girdled by rabbits and rodents that eat the bark tissues in winters. Plants that have stems girdled by animals often wilt and die suddenly in late spring or early summer after new growth begins.
Taking care of trees and shrubs is a year round job – be sure to interact with your plants this winter and keep an eye out for some of the above problems.