If you are transplanting a newly purchased rose, the timing depends upon how it is currently growing. Plant a rose growing in a container, or one you are currently growing in the ground, any time of the year in Mississippi. Plant bare-root roses in early spring.
Use a sharp spade to dig a deep, circular trench around the rose before prying it out of the ground. When you choose a new location, make sure there are no other plants within a 2-foot radius. This will help the rose tolerate Mississippi's humidity.
Dig the new hole for the rose 2 feet by 2 feet wide and 2 feet deep. This is the most important part of the planting process when planting bare root roses, although even potted roses benefit from a deep, wide planting hole.