Maintaining Rose of Sharon in your garden or yard is easy, but you should understand the natural environment that best suits the plant. Rose of Sharon is the common name of the Hibiscus syriacus, also known as Althea or Hardy Hibiscus. It is a beautiful deciduous shrub that grows in a wide range of climates. Carefully pruning the flower in its first two years helps ensure a healthy and beautiful plant.
Rose of Sharon Overview
Rose of Sharon grows best in full sun and can tolerate all but the hottest climates. If you live in a very hot climate, consider planting where the flower will receive afternoon shade. Winter temperatures down to -20 degrees Fahrenheit are acceptable for growing this flower, although winter mulch will be helpful in cold environments. The climate is most favorable in USDA Hardiness zones five through nine.
Water the plant regularly and keep the soil fairly moist, but keep in mind that overwatering may be harmful. Rose of Sharon will grow to approximately eight to 12 feet tall and six to 10 feet wide with leaves growing out later than those of many other deciduous shrubs. Bloom colors can be red, white, lavender, pink, or light blue, and some plants even have double blooms (double rows of petals that make for a fuller flower).
Tip: If you love the look of the Rose of Sharon, but do not have the space or the time for pruning, consider buying a miniature species such as Hibiscus syriacus, "Minerva," which reaches only five to eight feet tall.
Prune to Ideal Shape in the First Two Years
During the first two years, prune Rose of Sharon to a shape of your liking. Perform any heavy pruning in early spring, before the plant leafs out. Light pruning throughout the year will help maintain the shape and form of the plant.
Pruning techniques vary with your desired shape. For a fuller rounder bush, make "heading cuts" by shortening the preexisting branches. For a more natural, vase-like shape make "thinning cuts" by removing the entire stem. The Rose of Sharon is naturally a multi-stemmed shrub, though it can be pruned to have one main growth and is sometimes referred to as the Rose of Sharon tree.
Maintain Shape and Form with Light Pruning
Pruning Rose of Sharon in the early springtime encourages blooming while allowing you to remove any portions of the plant damaged by winter temperatures and winds. Cutting the shrub back to two or three buds per branch will encourage larger blossoms. You can give old or overgrown shrubs a new lease on life by pruning one third of the oldest main stems to the ground each spring for three years. After the third year, you will have a more compact and better flowering shrub. Remove dead, diseased, and injured branches at any time of year.
You can safely prune Rose of Sharon back to stubs of about two feet without damaging the plant. However, smaller pruning jobs will help to form a more natural appearance.
Because Rose of Sharon is a large shrub, it grows best when given a good deal of free space. Unless you are willing to prune it heavily each spring, do not plant Rose of Sharon in an area with limited space. Additionally, if you do plant it in a wide open area, it is not absolutely necessary to prune the plant at all.
Rose of Sharon should remain in the ground to overwinter. Do not fertilize the plant prior to the late fall and winter seasons, as a fair amount of seasonal damage is common. However, Rose of Sharon does well over the winter when insulated in a moderate to heavy cover of snow.