Rose of Sharon (Hibiscus syriacus) is a deciduous hibiscus species that produces abundant showy blooms in the summer and fall. The five-petal, paper-like flowers come in an array of colors (including bicolors) that reach three inches in diameter. Blooms have a prominent stamen and often a dark colored throat.
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.
|Common Name||Rose of Sharon, shrub althea, rose mallow, Syrian mallow, Syrian hibiscus|
|Botanical Name||Hibiscus syriacus|
|Mature Size||8–12 ft. tall, 6–10 ft. wide|
|Sun Exposure||Full, partial|
|Soil Type||Moist, well-drained|
|Soil pH||Acidic, neutral|
|Bloom Time||Summer, fall|
|Flower Color||Pink, purple, lavender, red, blue, white; often with dark throats|
|Hardiness Zones||5–8, USDA|
7 Helpful Tips on Growing the Rose of Sharon
Rose of Sharon Care
This shrub is tolerant of urban conditions, heat, humidity, poor soil, and drought. It's primarily used as a specimen, hedge, or foundation plant. It does readily self-seed, so be prepared to remove seedlings if you don't want more Rose of Sharon in your landscape.
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.
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.
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.
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 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
- '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.
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:
- Cut a pencil-wide stem that's four to six inches long. Remove the leaves from the bottom half of the stem.
- Dip the cut end of the stem into rooting hormone.
- Plant the bottom third to bottom half of the stem in a small container filled with soilless potting mix. Make sure the container has drainage holes.
- Water to lightly moisten the growing medium.
- Place a clear plastic bag over the container.
- Put the container in a warm spot with bright indirect light.
- Check the growing medium every few days to make sure it remains moist. Add more water if necessary, but don't let it get soggy.
- Remove the plastic bag after seven days.
- Check for roots in one to two months. Pull gently on the stem; if you feel resistance, the stem has rooted. New leaf growth is also a sign the stem has rooted.
- Wait for at least two inches of stem growth before planting it in your garden.
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.
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.
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.
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.
Is rose of Sharon easy to care for?
This shrub can tolerate a variety of growing conditions and doesn't need much maintenance. Pruning to keep the shrub's desired shape and to limit its spread is often the task that takes the most time.
How fast does rose of Sharon grow?
Rose of Sharon has a moderate growth rate, gaining about one to two feet per year.
Can rose of Sharon grow indoors?
The small rose of Sharon varieties can be grown in containers indoors; however, they need good air circulation and direct sunlight to thrive. So it's best to bring your plant outdoors during the warmer months.