Even with the most extravagant care, some types of roses tend to winter kill. These tender roses include most blue and lavender varieties, some white ones, and tree roses. Also, if the literature on your rose states that it blooms on old wood only, you are probably doomed to disappointment as most roses in our area must start over with new growth each year. However, all roses have a much greater likelihood of coming through the winter well if a few precautions are taken. First, continue watering your roses until the ground begins to freeze. Letting it go into the winter dry will almost certainly result in winter kill. Second, stop fertilizing your roses by the first of September so they can harden off. Allow the last roses to form hips, which helps the plant to stop growth and harden off for winter. After a couple of hard freezes, and the night temperatures are consistently below freezing, mound soil over the base of each bush to a height of 12 inches. Be sure to bring in extra soil to do this- don’t take it from around the roses, because you‘ll damage the roots. Cut excessively long canes back to about four feet and tie them together to prevent them from whipping around in the wind. When the mound has frozen over, cover it with straw, old sawdust, or some other fairly lightweight material that will insulate the mounds and keep them frozen. Waiting until the mounds are frozen before covering them can help prevent mice from making your rose bush a winter home. Building a cage around the rose with a wire mesh will help keep the insulating material in place. If you cannot build the cage, a burlap sack pulled down over the rose and then filled from the top with the insulation material is good, then tie the top shut and wrap it with twine to hold it in place around the rose. The objective of all these maneuvers, which are even more important in a mild or open winter, is to prevent the alternate thawing and freezing of the mound and canes which is the hall mark of winter kill. It also protects the canes from drying winter winds, also a common cause of winter kill.
