Rhododendrons should never need division. This holds true for most trees and shrubs. Division is appropriate for some perennials, but woody plants have a tough time regenerating a healthy root system. Rhododendrons rarely need pruning. They have a graceful, mounding branched habit that is particularly attractive if allowed to grow with minimal interference. If you need to shape or limit the size of a rhododendron, make pruning cuts in late spring after the plant blooms. Also, remove dead, diseased, and weak wood annually in late spring.