Rose of Sharon is a cold-hardy member of the hibiscus family, bringing pink, purple and white blooms to yards toward the end of the summer growing season and into early fall. To maximize bloom while keeping this energetic shrub under control, pruning may be necessary late in the winter or early in the spring. At maturity, Rose of Sharon is customarily 8-12 feet tall and 6-8 feet wide. Prune to make blooms visible at lower levels or to remove dead branches.
Prune Rose of Sharon in late winter or early spring. Flowers form on new growth, usually in May or June. Early pruning, therefore, stimulates shorter new growth without diminishing blooming.
Cut thin branches back to the heavy branches from which they grow. New shoots will form, shorter than what you have pruned, and multiple new shoots will make shrubs bushier.
Trim heavier main branches back only if growth is seriously out of control. Main branches can be cut back to 2-3 feet in height. Early spring remains the best time to conduct this major reshaping of your shrub.
New growth can be thinned after blooming for appearance, but major pruning should be done while the shrub is still dormant. Dead branches can be removed at any time.