Hibiscus are typically tropical flowering plants that cannot endure cold winters, but the hardy hibiscus called Rose of Sharon (Hibiscus syriacus) will succeed as far north as USDA climate zone 5 (Iowa and southern Illinois) where winter temperatures often dip below 0 degrees F. This pretty plant is often grown as a hedge, which creates a privacy screen with many attractive pink flowers. Early spring is the right time to prune your hardy hibiscus—they are adaptable to pruning into whatever shape or form you desire as long as you don’t cut off too much of its foliage and branches.
Examine your hardy hibiscus in early spring to determine the shape and size you want to create.
Moisten a clean rag with some of the water-free hand cleaner, hydrogen peroxide, isopropyl alcohol or bleach.
Wipe the blades of your clippers or loppers (depending on the size of the branches you are about to cut) with the damp rag to sterilize them. Allow the clippers to remain with the sterilizing solution on them for 15 seconds and then wipe them dry with another clean rag. Reapply your sterilization medium every few cuts.
Cut off damaged, dead or broken branches first—cut them all the way back to the main trunk. Cut off about a third of the plant’s healthy branches, making certain to leave two to three nodes per branch. To help the plant grow into the shape you want, cut ¼ inch above a node that is facing the proper direction.
Water your hardy hibiscus after you prune it and then give it an application of balanced fertilizer that you have diluted to half strength every week—this will encourage new growth in the spring.