Cold weather injury is one of the most prevalent causes of plant injury that is seen yearly. It’s one of the most under diagnosed issues as typically the damage is not seen until the spring when the event that caused it is long forgotten. Wilting leaves and a thinning canopy may be seen in a bountiful spring, and defoliation can occur weeks after a cold snap that only lasted a day. The cause behind this injury is water. Typically as we ease into the winter plants will gradually reduce the amount of water in their systems. In a cold snap, the temperature change happens to rapidly and the plant is not able to reduce the amount of water in its system, and ice forms. This ice will draw water from the cells and damage the plant tissue. The collapsed plant cells and the inability of the plant to move nutrients and water through its damaged systems will result in injury to the plant.
This damage can be seen in almost every part of the plant, from discolored feeder roots, to leaves having what appears to be tip burn. One of the ways to minimize the damage of winter injury is to maintain a general standard of health in your landscape plants with good cultural practices. Reduce plant stress by controlling any pest and diseases that your plants may be susceptible to. Also, incorporate hardy plant species into your landscape that are zoned for 7a-7b, and are not susceptible to winter injury. Here in Richmond, we are in a transition zone and can experience extreme temperatures on both sides of the thermostat. In most cases however, the damage is not permanent.