Q: Do you have any advice on the swamp hibiscus? The tag on the plant indicates that it “dies back to the ground in winter.” Info from a web site indicates that the plant will grow to 6 – 9 feet tall and that “the base of the plant will become quite woody.” But the same page recommends that “after re-growth in spring, tip prune to induce a more compact plant.” I don’t know what “tip prune” means, cut off the tips? I would like the plants to achieve their maximum height, so I don’t want them to be too “compact.” But on the other hand, if they die back to the ground in winter, then maybe they start all over again. By the way, they are planted in very moist soil, as required.
A: The Swamp Hibiscus (Hibiscus coccineus) does die back to the ground after the first frost. The “stalks” of the previous season’s growth take on a woody characteristic, but the plant does not re-grow from these. It starts new growth each year from the roots and in a single season will reach its mature height of 6+ feet. Since you want to let them reach their full height, don’t do any pruning on the new growth next spring. You can remove the dead stalks in December.