Rose of Sharon has a natural upright vase shape with multiple branches and medium to dark green foliage. However, it is possible to prune this shrub to a single trunk to produce a tree form. Rose of Sharon can be planted in the spring or fall, and it has a moderate growth rate of one to two feet per year. Young plants will need regular watering and feeding to help them get started. But mature shrubs typically don’t require much care. Plan to water during prolonged periods of drought. Prune regularly to keep the shrub to the desired shape.
Light
Rose of Sharon prefers full sun, meaning at least six to eight hours of direct sunlight on most days. But it also can grow in partial shade. However, too much shade can minimize flowering and contribute to diseases, such as fungal issues.
Soil
This shrub can grow in multiple soil types, including loamy, sandy, and clay soils. It prefers a nutrient-rich, well-draining soil with a slightly acidic to neutral soil pH, though it also can tolerate slightly alkaline soil.
Water
Rose of Sharon grows best in moist soil, but mature shrubs can tolerate some drought. It won’t thrive extremes: very dry or very wet conditions. So, don’t let the soil fully dry out, and make sure your shrub isn’t sitting in waterlogged soil.
Temperature and Humidity
These shrubs are heat lovers, but they also can withstand winters with below-freezing temperatures down to -20 degrees Fahrenheit. They also can handle high humidity if they have good air circulation. Otherwise, humid conditions can promote fungal growth.
Fertilizer
Fertilizer is recommended, though it’s not mandatory for established shrubs unless soil quality is poor. Use a slow-release fertilizer in the late winter or early spring, following label instructions. If your want to use organic growing practices, spread and work in an inch or two of compost into the soil around the root zone in the spring.
Types of Rose of Sharon
Here are a few popular varieties of Rose of Sharon:
‘Blue Chiffon’: This cultivar has double flowers (two layers of petals) with a purple-blue tinge that bloom from mid-summer into autumn. It grows 8 to 12 feet tall with a spread of six to ten feet. ‘Sugar Tip’: The name of this cultivar refers to its variegated leaves with creamy-white edging. It has pink double flowers and grows six to eight feet tall and four to six feet wide. ‘White Chiffon’: This variety is graced with solid white flowers; they do not have a contrasting throat. It grows six to eight feet tall and four to six feet wide. ‘Red Heart’: This shrub’s flowers are ruffled and feature white petals with dark red centers. Lovers of low-maintenance landscaping will be glad to hear that this is a sterile cultivar, so it won’t produce any seedlings to remove.
Pruning
This shrub grows naturally in an attractive form, so it doesn’t need much pruning. But you can tidy up its growth each year to maintain the size and shape you desire. Rose of Sharon blooms on new wood, so it should be pruned in the late winter or early spring to avoid cutting off any flower buds later in the season. Pruning back stem tips will encourage more branching and thus more flowers. Remove any damaged or diseased branches as they arise.
Propagating Rose of Sharon
The best way to propagate this shrub is by stem cuttings. Not only is this an inexpensive way to generate a new plant, but it also allows you to continue the lineage of a variety whose flowers you especially like. The best time to take cuttings is in midsummer. Here’s how:
How to Grow Rose of Sharon From Seed
Rose of Sharon readily self-seeds in the garden, and you can sow seeds as well. Start seeds indoors roughly 12 weeks before the last projected frost date in the spring. Fill a container with soilless potting mix, and plant each seed about a half inch deep. Lightly moisten the soil by misting it, and place the container by a bright window in a room that stays between 75 and 80 degrees Fahrenheit. Keep the soil consistently moist, and you should see germination in roughly two to four weeks.
Overwintering
Rose of Sharon doesn’t typically need any special winter care in its hardiness zones. Ideally, it should be situated in a spot that’s protected from strong, chilling, drying winds. If you live in a cold part of its hardiness zones, adding a layer of mulch around its roots also can help to insulate the shrub from extreme weather.
Common Pests
The chief pest problem for this shrub is the Japanese beetle. Japanese beetles are somewhat easier to control than many other insect pests because their large size makes them noticeable. That means you’ll likely spot them before they’ve done a lot of damage to your plant. The easiest way to kill them is to pick or shake them off the plant by hand and drop them into a container filled with soapy water. The insect breathes through its skin, so a coating of soap over its body effectively suffocates it.
How to Get Rose of Sharon to Bloom
Rose of Sharon readily blooms year after year if it has full sun and adequate nutrients and soil moisture. The showy flowers start to appear in midsummer and can stretch through mid-fall or even up until frost. The five prominent petals are slightly ruffled, and the tubular stamen at the center is very apparent. The blooms attract bees, butterflies, hummingbirds, and other pollinators. Deadheading (removing spent blooms) is not necessary to promote continued blooming. However, it will prevent the seed pods from forming, so it’s recommended if you want to limit seedlings from sprouting.
Common Problems With Rose of Sharon
This shrub is generally robust in its preferred environment. However, inadequate conditions can cause some common issues to arise.
Leaves Turning Yellow
Overwatering is often the culprit when your shrub’s leaves start to turn yellow. Make sure your shrub is planted in soil with sharp drainage and that it’s never in waterlogged conditions. It might be necessary to move your shrub if it’s located in a poorly drained spot.
Not Blooming
Several issues can result in a shrub that isn’t blooming well or at all. It’s possible you might have pruned too late in the spring and removed flower buds by accident. Drought also can minimize blooming, so make sure to give your shrub some supplemental water during very hot and dry spells. Furthermore, soil that’s deficient in phosphorus can result in low flower production and smaller blooms. Do a soil test to see whether you are dealing with any deficiencies, and apply fertilizer as needed.
