Summarize the following:
Generally speaking, Rose of Sharon is an exceptionally self-sufficient plant, and doesn’t require much upkeep. If you decide that your shrubs are in need of touching up, however, do it during the colder months while they’re still in their dormant stage. Doing so will help stimulate new growth once the weather warms up.  As a rule, the best time to prune your Rose of Sharon is anywhere from March to early May, before the blooms begin to open.  Cutting back your Rose of Sharon too early or too late can “shock” the plant, leaving it vulnerable to the elements and stunting healthy new growth. Pay close attention to any branches that appear rotted, brittle, or colorless, leaving only the strongest, healthiest sections behind. Try to shear each offshoot as close to the larger connecting branch as possible. You should be able to use your pruning shears to tackle most of the trimming.  For thick or stubborn branches, you may need to grab a pair of heavy-duty loppers or a handheld pruning saw.  If you’re not sure whether a particular branch is actually dead, try scraping off a little bit of the bark. If the wood underneath has a greenish tinge to it, leave it be. Inspect the interior of the shrub for offshoots that overlap or wind around each other. Clip off the more crooked of the 2 branches at its base—it’s not necessary to remove them both. Don’t forget to check for tangled or twisted stems near the outer part of the plant, as well. In addition to making your shrubs look better, getting rid of criss-crossing branches will also open them up in the middle, proving airflow essential for keeping pests and diseases at bay. Suckers are slender stalks that grow vertically out of the roots of woody shrubs like Rose of Sharon. They most often appear along the lower portion of the main branches or on the ground directly beneath the plant. The best way to deal with suckers is to snip each stalk as close to the base as possible, as this destroys their connection with the plant's roots and makes them slower to grow back.  Once they begin sprouting, suckers will typically return within a few months. This means you may need to cut them back 2-3 times a year.  Not only are root suckers an eyesore, they can also sap vital nutrients from the soil if they're not removed right away. If your Rose of Sharon isn’t faring well (or it’s grown to colossal proportions), it’s okay to remove quite a bit more growth than you leave. As long as the hardy living wood at the base of the plant is intact, it will return to produce eye-catching blooms year after year.  The practice of significantly reducing a plant's overall size is referred to as "hard" or "rejuvenation" pruning. Hard pruning is useful for promoting healthy new growth in old or failing plants. It’s safe to prune Rose of Sharon down to bare stubs that are only 2–3 feet (0.61–0.91 m) in length while it’s still dormancy. Keep in mind that the more branches you cut, the fewer flowers there will be when the shrub finally blooms. However, the flowers that are there will be much bolder and more vibrant since the plant will be able to devote more of its resources to the remaining growth.

Summary:
Wait until winter or early spring to prune Rose of Sharon. Clear out dead or damaged wood. Eliminate criss-crossing branches. Remove any visible suckers from the base of the plant. Cut your shrubs back by up to two thirds of their total size.