Rose Of Sharon: How To Grow and Care For Hibiscus Syriacus

Want big, hollyhock-like flowers in late summer, when most shrubs are done for the year? Meet rose of sharon (Hibiscus syriacus), also sold as althea or shrub althea. It is valued for large flowers produced in summer when few other shrubs bloom.

It’s a tough, easygoing shrub: a vigorous, upright, vase-shaped, multi-stemmed deciduous shrub that typically grows 8 to 12 feet tall, with showy 5-petaled flowers from early summer into fall. It makes a handsome privacy hedge, screen or specimen.

Plant it in the right spot, prune it at the right time and keep an eye on the seedpods, and it pretty much takes care of itself. Here’s how.

Rose Of Sharon Quick Care Tips

Botanical name: Hibiscus syriacus (former names include Althaea frutex, Hibiscus acerifolius and Ketmia syriaca)
Common names: Rose of sharon, shrub althea, althea, rose of China, Syrian hibiscus
Pronunciation: hi-BIS-kus seer-ee-AY-kus
Family and origin: Malvaceae (mallow family); native to China and Taiwan, though some references give China to India
Type: Deciduous shrub that can be trained as a small tree
Hardiness zones: USDA 5 to 9 (also listed as 5a to 9b and 5B to 9A)
Size: 8 to 12 feet tall and 6 to 10 feet wide
Growth rate: Rated anywhere from slow to moderate up to rapid
Flowers: Single or double, in red, pink, white, purple, lavender and blue; each flower lasts one day; June to October
Light: Full sun to part shade; best flowering in full sun
Soil: Moist, well-drained soil is best; tolerates poor soils, clay and a range of pH
Water: Regular water while it establishes; moderate drought tolerance later
Fertilizer: Go light; overfeeding invites aphids and bud drop
Pruning: Late winter or early spring; it blooms on new growth
Pests and diseases: Japanese beetles, aphids, whiteflies; leaf spots, blights, rusts and canker
Propagation: Stem cuttings; seedlings may not match the parent’s flower color
Pet safety: Non-toxic to dogs, cats and horses
Uses: Hedge, screen, specimen shrub, small tree, patio container

Rose Of Sharon Is Not Tropical Hibiscus (Or Hardy Hibiscus)

The name causes plenty of mix-ups. Clemson Extension treats three hibiscus separately. Chinese hibiscus (Hibiscus rosa-sinensis), the tropical one, is hardy in South Carolina only in the small coastal Zone 9 area, so it is usually grown as a summer annual or houseplant there. Rose mallow (Hibiscus moscheutos) is a Southeastern native perennial hardy in zones 4 to 9, and perennial hibiscus freezes back to the ground each winter in all but the warmest parts of South Carolina. Rose of sharon is a durable deciduous shrub hardy in zones 5 to 9.

So rose of sharon is a woody shrub that drops its leaves in winter. It is not its tropical hibiscus cousin that comes indoors for the cold months, and it is not the hardy hibiscus that dies back to the ground. Here are more differences between rose of sharon and hibiscus.

Where Will You Plant It?

Sun. Rose of sharon grows in full sun to part shade, and the best flowering occurs in full sun. Some protection from mid-day or afternoon sun is good for the plant’s appearance.

A single lavender-purple rose of sharon flower with a burgundy center blooms among toothed green leaves and a closed bud in a sunny garden.

Soil. It grows best in moist, well-drained soils but tolerates all except extremely wet or dry soils, and it is pH adaptable. It prefers moist, organically rich soils but tolerates poor soils, clay and some drought.

Heat and humidity. No need to fuss over a humidity number or a narrow temperature range for this shrub. It prefers hot weather and is very tolerant of summer heat and humidity.

Space. Give it room. It grows 8 to 12 feet tall and 6 to 10 feet wide, so consider its space needs when you pick the spot. For a hedge, plant in multiples 6 to 12 feet apart. Remember it is deciduous, so a rose of sharon hedge screens best from late spring through fall.

Tough spots. It is moderately tolerant of salt, deer, heat and wet soil, and it also tolerates drought, clay soil and black walnut.

Short on ground space? It works in containers and planters, trained as a standard, and for deck or patio use, and it can be trained as a small tree or espalier. That’s why it shows up among outdoor potted trees for the patio.

How To Plant Rose Of Sharon

Plant your new shrub as soon as you can after you bring it home. If it has to wait, keep the root ball from drying out. University of New Hampshire Extension says container plants can need water daily in summer while they wait.

Be Ready To Dig (But Not Too Deep)

Here’s the most common mistake: a hole that’s too deep and too narrow. Dig only as deep as the height of the root ball and two to three times as wide as its diameter. The wide hole loosens the soil so new roots can spread. Need a refresher? Here’s how to dig a $10 hole.

Two fully double, ruffled pink rose of sharon blooms with round buds stand among leafy green shrubs in a sunlit mulched garden border.

Get It Out Of The Pot

Slide a potted plant out sideways on the ground, and handle plants by the container, not the trunk or branches.

Then look at the roots. If small roots circle the outside of the root ball, slice down the sides in three or four places, an inch or two deep, to cut through those circling roots. On larger plants, cut any circling roots thicker than about a quarter inch with hand pruners and remove any mat of roots at the bottom.

Backfill And Water

Set the shrub in the center of the hole and check that it sits at the right depth. Fill around the root ball with the soil you dug out, minus the rocks. In most cases there’s no need to amend that soil with organic matter. For very heavy clay or very sandy soil, mixing about 10 percent compost or peat moss (by volume) into the backfill may be worthwhile. A soil test ahead of time tells you if lime or nutrients are needed.

A water-droplet-covered pale pink rose of sharon flower with a deep red veined eye blooms amid toothed green leaves against a house wall.

Firm the soil by hand or tamp it lightly with your foot as you go. Adding water when the hole is half full helps settle the soil; water again when you finish. Right after planting, water slowly but thoroughly so the whole root ball and backfill are soaked.

Worried about drainage? Do a percolation test before you plant: make sure water drains from the hole completely within 24 hours.

Protect The Roots With Mulch

Mulch helps keep the soil moist, moderates soil temperatures and gives a new shrub an edge over grass and weeds. Spread it 2 to 3 inches deep over the whole root ball and out to at least the drip line (the edge of the branch tips).

A multi-stemmed rose of Sharon shrub blooms with pink flowers above a wide mulch ring beside a white porch railing on a sunny day.

Keep it off the stems. Piling mulch against the trunk can lead to disease and insect problems at the base, so pull it back a few inches. Keeping mulch from touching the stems also helps prevent southern stem blight on hibiscus.

Rose Of Sharon Care

Watering

A new shrub needs steady water. Water frequently for the first few weeks, every other day if there’s no rain and the soil drains well. Each time, give it enough water to wet the soil a foot deep, about an inch in well-drained soil, and skip it when you get more than an inch of rain or the soil is still moist. Shrubs usually settle in during their first year.

Slow and deep beats a quick sprinkle. Water applied slowly so it soaks in is much better than water applied fast with a hose, and drip irrigation or soaker hoses may be worth it for larger plantings.

Don’t drown it, though. In clay or poorly drained soil, the loosened soil of a new planting hole can fill up like a bathtub and drown the roots. Soggy soil is how root rot gets started.

Once it’s established, rose of sharon is fairly forgiving. Its drought tolerance is moderate, but it needs ample moisture to flower its best and to avoid leaf drop.

Feeding

Go light. A new plant doesn’t need added nitrogen fertilizer in its first year, and soluble fertilizers may even slow root growth. Wait until the next spring, then apply a slow-release fertilizer over the root zone, following soil test results. Rose of sharon tolerates poor soils.

Too much food causes its own trouble. Over-fertilizing increases aphid infestations and can cause bud drop. If you like compost, a thin layer can be used as mulch, and covering it with a coarser mulch such as wood chips helps prevent weeds. For product details, see our guide to rose of sharon fertilizer.

Watch Out For Bud Drop

Buds falling before they open? Bud drop can be caused by too much or too little water, or by over-fertilization. Check your watering first, then your feeding. If leaves are yellowing too, see these reasons for hibiscus dropping blossoms and leaves.

Pruning

Rose of sharon blooms on new growth, which makes pruning simple. Prune in late winter or early spring in northern climates. Spring pruning encourages flowers on new growth and increases flower size. Prune to shape in spring; cutting back to 2 to 3 buds in late winter may produce larger blooms.

Big flowers or lots of flowers? You choose. Frequent severe pruning gives fewer but larger flowers, while little or no pruning gives many smaller flowers. Pruning is usually not required, though.

Skip the fall haircut. For shrubs in general, the best time to prune severely is before spring growth begins, and pruning in late fall or midwinter may encourage new growth that cold can injure.

Start every pruning job the same way. The first step in pruning a shrub is to remove all dead, diseased or injured branches, then branches that cross or rub. If you spot canker, prune out the infected branches. More tips are in our guide to hibiscus pruning.

Spent Flowers And Seedpods

Each rose of sharon flower lasts just one day; individual flowers stay open for one day and close at night. After the flowers come the seed capsules, which persist through winter.

Those capsules are worth your attention. The Missouri Botanical Garden says species plants can self-seed aggressively in good growing conditions, and some cultivars readily produce offspring from seed. Virginia Cooperative Extension‘s Master Gardeners of Northern Virginia say rose of sharon must be deadheaded to control it in the garden, and that even tiny volunteer seedlings are woody and hard to pull. Snip off faded flowers and young seedpods before they open. Here’s how to deadhead hibiscus.

Is Rose Of Sharon Invasive?

In some regions, yes. NC State Extension says rose of sharon has been reported to be invasive in some states, including Virginia and Kentucky. This prolific seeder has escaped cultivation in much of the eastern U.S. and is reported as invasive in Virginia, specifically in Arlington and Alexandria. It escapes into natural areas and crowds out native plants, and its many seed pods are spread by wind.

What about the roots? Descriptions differ. Established plants can be very difficult to remove because of a strong, deep taproot, yet other references say several roots are usually found just beneath the soil surface and rate the roots as not a problem.

If you garden in an area where it spreads, deadhead faithfully or consider a native alternative. Good choices include Muenchhusia laevis and Muenchhusia moscheutos (formerly Hibiscus laevis and Hibiscus moscheutos), scarlet rose-mallow (Hibiscus coccineus), halberd-leaf rose-mallow (Hibiscus laevis) and swamp rose-mallow (Hibiscus moscheutos).

Rose Of Sharon Winter Care

Good news: rose of sharon is cold hardy. It is usually listed as hardy in USDA zones 5 to 9 (5a to 9b or 5B through 9A in some listings), though the most cautious rating is 5 to 8.

Tall upright rose of sharon shrubs covered in ruffled lavender-pink blooms and toothed green leaves, with a bee visiting one flower in a sunny garden hedge.

It is not evergreen. Rose of sharon is deciduous, so bare branches in winter are normal, not a sign of trouble. Keep the mulch in place (mulch moderates soil temperatures), and let the pruning wait until late winter. For general cold-weather protection in the garden, see these tips to minimize winter injury to trees and plants.

Pests And Diseases To Watch For

Rose of sharon doesn’t get many problems. It is usually strong and easy to grow and resistant to pests and diseases. Japanese beetles, whiteflies and aphids are occasional insect visitors.

Japanese beetles. These are the big one. Japanese beetles can severely damage the foliage if left unchecked, and in northern gardens they are particularly fond of the flowers. University of Minnesota Extension says handpicking works well on a few plants: handpick or knock the beetles into a bucket of soapy water. It also says not to use Japanese beetle traps, because they attract more beetles than they catch. If you use an insecticide, follow the label, and remember the flowers draw bees; several common beetle insecticides are toxic to bees. Skip malathion entirely: UF/IFAS says in its hibiscus guide to read labels carefully, because you should never use the pesticide malathion on hibiscus, and rose of sharon is a hibiscus.

Aphids. Aphids gather at the tips of stems, cause misshapen new growth and can coat leaves with sticky honeydew. Knock them off with a strong spray from the hose or pinch off the infested tip, and go easy on fertilizer. More here: aphids also attack rose of sharon plants.

Diseases. Rose of sharon has some susceptibility to leaf spots, blights, rusts and canker. Pick off and destroy leaves with leaf spot. Canker can kill branches or whole plants; look for bright reddish-orange fruiting bodies on the bark and prune out infected branches. Keeping mulch off the stems helps prevent southern stem blight.

Is Rose Of Sharon Safe For Pets?

Yes. The ASPCA lists rose of sharon (Hibiscus syriacus) as non-toxic to dogs, cats and horses. That still doesn’t make it a chew toy, so keep an eye on pets that like to snack on the garden.

Rose Of Sharon Flowers, Colors And Wildlife

The single or double flowers come in shades of red, pink, white and purple, depending on the cultivar, and in blue and lavender too. Expect 2- to 4-inch flowers with five crepe-like petals in red, white, violet, purple or two-toned forms. Each has a showy center column of stamens.

Two lavender-blue rose of sharon flowers with red eyes bloom on a leafy shrub, with blurred pink double flowers in the background garden.

Want a particular look? Cultivars include ‘Aphrodite’ (rose flowers), ‘Blue Bird’ (blue flowers), ‘Diana’ (large pure white flowers that stay open at night), ‘Lavender Chiffon’, ‘White Chiffon’ and ‘Red Heart’ (white with deep red centers). Prefer white? ‘Diana’ and ‘White Chiffon’ are two to look for. Prefer blue? ‘Blue Chiffon’ has pale lavender-blue flowers.

Pollinators love it. The flowers attract butterflies, specialized bees and hummingbirds, which makes rose of sharon a good pick for pollinator, butterfly and children’s gardens.

Want more plants? Rose of sharon is easily propagated by stem cuttings, but plants grown from seed may not have the same flower color as the parent. Here’s how to propagate and start new rose of sharon cuttings.

Whether you’re new to gardening or an old hand, rose of sharon is an easy shrub to love. What color is blooming in your yard? Tell us in the comments!