8 Plants can also be injured when mid-winter temperatures drop below a plant s maximum hardiness level. Rapid deacclimation in response to warm temperatures in late winter will also leave plants vulnerable to injury by subsequent freezing conditions. A variety of winter injury patterns were seen among the roses. Some species and cultivars exhibit no injury at all. Others show tip injury, where a small amount of dieback occurs at the ends of canes.
Snow serves as a natural insulator of plants, and many rose cultivars die back to the snowline.
Those parts of the canes exposed to the cold air above the snow die, while the lower parts of canes covered with snow survive. There are also cultivars that show variation in injury pattern from cane to cane. Within one plant, canes with no winter injury can be found next to canes that are either partially or completely killed. Other cultivars behave much like herbaceous perennials, dying back to the ground every winter. Canes are hardy to the tip.