Prune dead and broken branches at any time during the growing season by cutting them back to their points of origin.
Cut down the swamp hibiscus' height to where you want it. Use sharp pruning shears to avoid shredding the stems.
Pinch prune the swamp hibiscus when new stems reach 6 inches in length. Use your thumb and forefinger to pinch off the bud at the tip of each stem. This encourages the plant to grow fuller.
Wait until the swamp hibiscus dies back in winter to cut all stems to the ground.