Rose of Sharon bears many blooms, and its attractive flowers are its main selling point. Like other types of hibiscus, its flowers bear a striking stamen. Another feature giving the shrub value is its relatively late period of blooming (in the northeastern United States, it blooms in August). Rose of Sharon is thus able to offer white, red, lavender, or light blue blooms when many flowering shrubs have long since ceased blooming. It is critical for gardeners to be able to grow such late summer flowering shrubs if they are intent on managing sequence of bloom in their landscapes.
Contrary to its name, the plant is not really a rose at all, instead, it is a member of the Malvaceae or mallow family. Nor is it native to Syria, as is suggested in its species name Hibiscus syriacus. This plant's origins hail from India and China.
- Botanical Name: Hibiscus syriacus
- Common Name: Rose of Sharon, Althea, Korean rose, rose mallow, Chinese hibiscus
- Plant Type: Deciduous shrub
- Mature Size: 8 to 10 feet tall with widths half that
- Sun Exposure: Full sun to partial shade
- Soil Type: Rich and moist
- Soil pH: Acidic to slightly alkaline
- Bloom Time: Late summer, early fall
- Flower Color: White, red, lavender, or light blue
- Hardiness zones: 5 to 9
- Native Area: China, India
How to Grow Rose of Sharon Plants
The plant thrives in moist, well-drained soil. Rose of Sharon is tolerant of air pollution, heat, humidity, poor soil, and drought. This species has naturalized well in many areas and can become invasive if growth is not monitored.
Rose of Sharon prefers full sun. Older bushes may fall prey to fungal damage if you are growing them in areas without full sun. That is because excess moisture is retained in shaded areas, and it is precisely in moist conditions that fungus thrives.
This plant thrives in rich soil. It can tolerate many soil types from sand, clay, chalk, and loam. It prefers nutrient-rich soil but can survive in poor soil, too. Rose of Sharon thrives in a wide range of soil pH from 5.5 to 7.5 on the pH scale.
Temperature and Humidity
A heat-lover, this shrub is also prized by growers in the southeastern U.S. who crave plants that can stand up to summer's heat.
Fertilizer is recommended (although not mandatory for established shrubs). If you wish to grow organically, work compost gently into the soil around the root zone and water it into the earth.
Propagating Rose of Sharon Plants
The best way to propagate rose of Sharon plants is by making stem cuttings and potting them.
- Cut several pencil-wide branches of rose of Sharon that have several leaves or leaf buds. Cut the stems 4 to 6 inches long and remove the leaves from the bottom half of the stem.
- Dip the end of the stem in rooting hormone. Plant the bottom third or bottom half of each stem.
- Place a piece of clear plastic over the top of each pot. Water well.
- Put your pots in a spot with shade or indirect light. Remove the plastic in seven days. Check the pots every few days to make the potting mixture remains moist. Add more water if needed, but do not let the soil get soggy.
- Check the cuttings for roots in one to two months. Pull on each stem; if do not feel give, the stem has rooted. You also should also see new leaves form on the branch stems that have rooted.
- Grow them larger, at least two inches of growth, before planting them in the garden.
Although naturally a multi-stemmed shrub, this plant can be trained through pruning to have simply one main trunk; thus some people refer to it as the rose of Sharon "tree." Prune in late winter or early spring, since this is one of the shrubs that bloom on the current season's growth. It is easiest to give rose of Sharon its desired shape by pruning it accordingly during its first two seasons. It can also be trained for espalier (grown flat against a supporting structure).
Also, do not give up on rose of Sharon, thinking it is dead just because it has not leafed out by early summer. This shrub not only blooms late but leafs out late, as well, so be patient. When its flower buds are not opening, that is another matter.
Watch Now: 7 Helpful Tips on Growing the Rose of Sharon
This shrub is primarily used as a specimen plant, hedge plant, and foundation shrub. Its attractive and plentiful blooms make this plant fully capable of holding its own as a specimen. Your ability to shape rose of Sharon also makes the shrub a prime candidate for hedges. But since this bush is deciduous, it makes an effective privacy hedge only in summer (select one of the evergreen shrubs to gain privacy all year).
You can use it as a privacy shrub around swimming pools in regions with cold winters since you would most likely be doing your swimming there only during the summertime. However, its blooms could attract bees, which are usually unwelcome in poolside areas. Because the shrub responds well to annual pruning, it is quite useful in foundation plantings, where it is important to be able to manage a plant's growth. You want to avoid having it eventually overwhelm your house.
Those are not the only pesky problems associated with growing Hibiscus syriacus. Its seed drops and sprouts where you do not want it to, and the consequent need to remove the young plants manually is hardly conducive to low-maintenance landscaping. There are many ways of getting rid of its seedlings than by pulling them, so do not let this issue dissuade you from growing these lovely shrubs.
The chief pest problem for this bush is Japanese beetle infestations. Japanese beetles are somewhat easier to control than many other insect pests because they are large enough to spot immediately before they have done too much damage to your plants. The easiest and safest way to kill them is to pick or shake them off by hand, dropping 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.
Varieties of Rose of Sharon
- Tri-color: On this cultivar, pink, purple, and red double blooms occur on the very same shrub
- Pink Giant: The size of its flowers are large, 5 inches in diameter, pink, with red centers
- Diana: Unlike most kinds of rose of Sharon, it has solid-colored flowers: white, with no "throat" of a different color. They stay open at night, making them especially useful for moon gardens.