Fall is the best time to transplant potted roses in mild climates. Once roses have been transplanted, they will be able to spend the winter developing their roots under the soil. The key to successfully transplanting a rosebush is to minimize the roots' exposure to light and air.
Always wear protective clothing and gardening gloves when working with roses as they have sharp thorns that can injure you.
Prune your rosebush as you normally would for fall. Cut back dead branches, weak stems and any branches that crisscross or rub. You should never remove more than 2/3 of the plant's mass in a single pruning. When transplanting, however, it's best if the root mass is greater than the stem mass.
Select a location for the rosebush that has well-drained soil and gets at least 6 hours of sunlight daily.
Dig a hole that is 15 inches deep and wide enough to accommodate the root-ball. Work compost into this hole with a garden fork. Water well and wait at least 48 hours for the compost to settle into the soil.
Thoroughly water your potted rosebush 2 days prior to transplanting it.
If possible, transplant your rosebush on an overcast day. Build up a moundof soil in the center of the newly dug hole upon which to place the root-ball. Gently remove the rosebush from its pot and place the root-ball on the soil mound inside the hole you dug earlier. Spread the roots around the sides of the mound. Backfill the hole partway with excavated soil. Fill the hole with water and wait for it to drain and settle before filling the hole with the remainder of the soil. Water again.