Many gardens lose their color once the summer heat kicks in. Choosing hardy bloomers that can handle the heat and full sun will keep your green spaces looking bright and beautiful. The Rose of Sharon, native to India and eastern Asia, not only thrives during the hottest months of the year, but it also holds up to frigid winters, air pollution, and humid conditions. Its exotic, long-lasting blooms and vibrant green foliage flourish year after year without a lot of fuss.
Surprisingly, Rose of Sharon, or Hibiscus syriacus, is not a rose. But it is related to hibiscus, cotton, and okra and a member of the Mallow family. This deciduous shrub grows upright, reaching heights of eight to 12 feet with a spread of up to 10 feet. The plant usually has multiple trunks. Its thin, silky, trumpet-shaped flowers appear on the current year’s growth and can reach up to four inches across. Choose from white, pink, red, violet, or purple blooms. These flowers open in sunlight and close in the dark. In October, the blooms fade and develop into seed pods, which become a source of food for a variety of birds.
This shrub adapts well to most USDA hardiness zones. Choose a planting spot where the bush will have access to full sun for optimal blooming. The soil should be moist but well-drained with acidic to slightly alkaline pH levels. Plant seeds that began growing indoors and transplanted, or buy healthy plants from a nursery. Dig a hole that’s twice the width of the pot, place the plant into the hole and add some compost. The crown of the plant should sit at or just above the soil line—water well after refilling the hole and cover the area with a layer of mulch. If planting multiple shrubs, space them six to 10 feet apart.
Overfeeding this shrub will cause its leaves to turn brown and drop, plus, fertilizer promotes foliage growth instead of blooms. Look for fertilizers that are high in potassium with a medium amount of nitrogen and low phosphorus and apply once per year. Never fertilize after July. It encourages new growth, which makes the shrub susceptible to frost damage.
Gardening experts suggest cutting Rose of Sharon back to a height of four to six inches before new growth starts to emerge in the late winter or early spring. If you prefer a fuller shrub with bigger flowers, cut the plant back to one-half its size in late spring. Through careful pruning in the first two years, you can easily train these plants to grow against a supporting structure. Or, prune it to have a single trunk so that it behaves and looks more like a tree. Remove all suckers that appear at the bottom of the trunk. Snip off fading flowers and their seed pods to prevent spread.
In the first few weeks after you’ve planted the shrub, you may need to water it two to three times a week to keep the soil moist. Don’t overdo it, however. Overwatering is more of a problem than underwatering for this drought-tolerant shrub. If the soil stays wet much of the time, your Rose of Sharon won’t thrive. The plant’s roots will rot, and it could die. Yellow leaves are a sure sign that the plant is getting too much H2O. Correct drainage problems quickly to avoid issues.
Need a way to make your outdoor space a little more private? Grow a beautiful living fence or privacy hedge with the Rose of Sharon. Plant shrubs in a straight line, six to 10 feet apart, depending on their expected maturity size. You’ll find that information on the plant’s tag when you purchase it. If you’re creating a large flower bed, plant Rose of Sharon in the back to add height. Arrange shorter flowering plants and shrubs in front to add depth and visual appeal. If you have a bare spot or corner in your yard, the Rose of Sharon’s showy flowers and widespread growth makes it the perfect stand-alone choice.
This plant’s most likely enemy, the Japanese beetle, isn’t difficult to control. Once discovered, these bugs are big enough for gardeners to shake or pick off the plant’s blooms. Horticulture specialists advise removing them, then dropping the pests into a container of soapy water to end the infestation. Large holes or skeletonized plants are signs of the infestation. Keep an eye out for root-knot nematodes as well. If your shrub starts to wilt and dry up, this is likely the cause. A sticky residue on the leaves of your Rose of Sharon means your plant has an aphid problem. Ladybugs, frogs, and toads consume aphids in the natural world. If there’s none around, try spraying aphid-ridden plants with a soap-and-water mixture.
Experts produce plant varieties called cultivars through selective breeding. Rose of Sharon can be invasive in some areas of the country, primarily in the southeast region. To curb its invasive nature, the U.S. National Arboretum created three Hibiscus syriacus cultivars that don’t spread: the Aphrodite, the Helene, and the Minerva. Other sterile cultivars include Azurri Satin, Sugar Tip, Lucy, Lavender Chiffon, and Diana. These varieties are widely available online or at local gardening centers.
Because it’s a vigorous bloomer, Rose of Sharon also produces a lot of seeds. Seeds that drop to the ground after the flower fades will likely self-seed in a big way. Even if you want to produce more shrubs, it’s a good idea to control the process. First, start deadheading the flowers in October after the pods have dropped the seeds. Some gardeners place a nylon bag under the shrub to catch the seeds as they fall. Plant in ¼ to ½ inch soil in spring, making sure they’re getting full sun and plenty of water.
No matter what time of year it is, you can take parts of the Rose of Sharon and create a new plant. You’ll need some rooting hormone and soilless potting mix. In early to midsummer, cut some of the green shoots that emerged from the plant in the previous spring. If it’s in the late fall or early winter, take hardwood cuttings instead. The stems should be between four and 10 inches long. Remove the leaves, except for a few at the top. Dip the cut ends in rooting hormone and stick them in a pot filled with the soilless potting mix. You’ll soon see roots and new foliage appearing on the new plant.