Hardy hibiscus are a blooming hibiscus variety that are hardy to USDA zone 5, as opposed to tropical hibiscus plants that cannot withstand anything more than an occasional light freeze. Each winter, a hardy hibiscus plant will die back and then the hibiscus plant will grow again the following spring. Gardeners need not perform extensive pruning on hardy hibiscus plants other than controlling the shape and growth of the plant during the growing season and cutting back the dead growth in late fall.
Watch for the hardy hibiscus plant to sprout in the spring. As the new growth gets going, allow it to grow without interfering for approximately one month.
Use the pruning shears to prune approximately 2 inches from the tips of the stems carefully. This will shape the hardy hibiscus and encourage bushy lateral growth. Use this pruning to control the size of the hardy hibiscus plant also. If the plant is growing too large, prune it back more extensively to the size you desire.
Allow the plant to die back completely in the autumn. When the entire hardy hibiscus plant wilts dramatically, cut back this foliage so it is approximately 10 inches high.
Apply 2 inches of mulch around the base of the hardy hibiscus to protect the roots from winter temperatures.
Cut off all of the old foliage down to the soil level in the spring prior to new growth appearing.