How do I over-winter a tree rose?
Tree or standard roses are produced by bud-grafting the desired rose variety onto a tall stem. Since the cold-sensitive bud union may be 2 or 3 feet above the ground, tree roses are extremely vulnerable to winter injury or death. (Tree roses are best suited to areas with mild winter climates.)
The first step in protecting a tree rose is to decide which direction to lay the plant. Then loosen the soil in the opposite direction with a spade. Put the blade into the soil about 1 to 1½ feet from the base of the stem. Then gently rock the spade back and forth to loosen the soil and free the roots. Loosen the soil in a semicircle around the plant. On the other side of the tree rose, dig a trench to accommodate the plant and then carefully bend the trunk (stem) down to the ground. Peg the stem down with stakes. Finally, completely cover the tree rose with several inches of soil.
Prepare tree roses for winter after plants have been hardened by exposure to several nights of temperatures in the low to mid-twenties. Normally, this is early November in northern Iowa, mid-November in central areas, and late November in southern counties.
Tree roses growing in pots or other containers also need winter protection. One method is to dig a trench in the garden, lay the potted tree rose in the trench, then cover it with several inches of soil. Another method would be to place the potted tree rose in a cool garage or shed. Temperatures in the storage area should be consistently in the 30’s and lower 40’s.