When they've been recently planted, it's a good idea to forego pruning for a while. Previously, the advice was to do a little pruning when you plant, but now university studies have shown that plants unpruned at transplanting time recover from the transplant shock more quickly. The plants use every bit of their leaf surface to produce the energy their root systems need to establish themselves in the new site. In the future, you can prune your Hibiscus (also called Rose-of-Sharon and Althea) each spring. They respond well to an all-over cutback; you can cut them clear down to 6-10 inches from the ground if you wish.