Answer: Hardy hibiscus will normally die back to the ground during the winter, so simply cut them back to the ground and remove the stems altogether once that happens. You might also place a layer of mulch atop their location. Mark their location ( maybe leave the tomato cages in place) because they emerge very late in the spring and are easily "misplaced" in the spring planting rush. They will grow to their full size again from scratch next year but should add one or two more stems to their bulk each year.
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