Shrub · Malvaceae
Rose of Sharon
Hibiscus syriacus
Plant it in full sun with a little breathing room, and this easygoing shrub will keep the garden in color from midsummer to frost.
Full sun
Every 7–14 days
USDA 5–9
8–12 ft · 2.4–3.7 m
Overview
If you have ever worried that the garden goes quiet once high summer fades, Rose of Sharon is the shrub that puts that worry to rest. It is an upright deciduous shrub in the mallow family, and it opens fresh, hibiscus-shaped flowers one after another from June all the way into October. You will find blooms in white, pink, lavender, and an uncommon violet-blue, and many of them wear a contrasting eye at the throat that makes each flower feel like a small gift.
The best part for a nervous first-time grower is how hard this plant is to discourage. Once its roots settle in, it takes heat, humidity, drought, and poor soil in stride, and it comes through winters as cold as -20°F (-29°C) without any fuss. It grows fast and can reach 8 to 12 feet (2.4 to 3.7 m), so even if you feel unsure at the start, you will likely end up with a generous screen or a reassuring anchor at the back of a border.
The one habit worth knowing about is its eagerness to self-seed, which has it flagged as invasive in a few states. That sounds worse than it is, because the fix is simple: if stray seedlings would be a bother where you garden, just choose a sterile cultivar like Diana and you keep the long season of bloom without the spread.
Care
The short version: give it a sunny, well-drained spot, water it faithfully through its first season or two while it finds its feet, then cut it back in late winter and let it carry the late-summer show on its own.
Light
Aim for full sun, since that is what brings on the heaviest flowering, but do not fret if the spot gets some partial sun or light afternoon shade, because the plant will still do well. As a simple rule, the more sun it soaks up, the more blooms you get to enjoy all summer long.
Water
While your plant is young, water it regularly and deeply so the roots have every reason to reach down, rather than giving it frequent little sprinkles. After a season or two, once it has truly settled in, it becomes wonderfully drought tolerant and gets by on medium moisture and ordinary rainfall except in the driest stretches.
Soil
Good news: this shrub is not picky about soil and will grow in average, well-drained ground of just about any pH. It even forgives poor sites, but it does ask for decent drainage, since soggy roots are one of the very few things that can truly set it back.
Temperature
This is a genuinely tough plant that shrugs off a wide sweep of temperatures, from about -20°F to 100°F (-29°C to 38°C). It handles summer heat and humidity calmly and comes through hard winters on its own, with no protection needed on your part.
Humidity
You will never need to fuss over humidity here, because average outdoor air suits it just fine. What helps far more is good air movement, since crowded, stagnant air is what invites the leaf spots and rusts it can otherwise pick up.
Feeding
In decent soil it barely asks to be fed, so there is no need to overdo it. One helping of balanced general-purpose fertilizer in spring is plenty, and leaning heavy on nitrogen only encourages the soft new growth that aphids find irresistible.
Pruning
Because it flowers on new wood, you can prune with confidence in late winter or early spring before growth starts, and there is little you can do to harm it. Cutting the stems back hard, to 2 or 3 buds, trades a few blooms for noticeably larger ones and tidies the shape at the same time.
Repotting
A container plant here rarely needs moving, so you can leave it be most years. Step it up to a larger pot only when you notice roots circling or slipping out the drainage holes, water running straight through, or growth that seems to have stalled.
Size & spacing
Give it space to be itself: this is a fast grower that reaches 8 to 12 feet (2.4 to 3.7 m) tall and spreads 6 to 10 feet (1.8 to 3 m) wide. Leaving that much room lets air drift through the branches and keeps the leaves dry, which heads off most trouble before it starts.
When to plant
Rose of Sharon takes its time, leafing out late in spring and saving its energy for a long show that runs from June well into October. There is no rush and no tricky window to miss: set new plants out in spring once the last frost has passed, or in early fall, and save the season's pruning for late winter before the buds wake up.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: late winter to early spring (8-10 weeks before last frost)
- Plant: spring after last frost, or early fall
- Harvest: June to October (mid to late summer)
Hardiness
USDA hardiness zones: 5–9
Temperature: down to -29°C
Troubleshooting
Take heart, because this shrub is one of the most trouble-free you can grow, and nearly everything that bothers it is cosmetic rather than serious. The pests and spots below tend to appear on the leaves and buds first, so a gentle look over the plant now and then through summer is all it takes to catch them while they are still easy to handle.
Summer leaves nibbled down to lace
Those lacy, see-through leaves are the work of Japanese beetles, which gather in groups on warm days and chew the soft tissue away between the veins. Do not panic, because the simplest cure works well: pick the beetles off by hand in the cool of early morning and drop them into a bowl of soapy water. It is worth skipping the pheromone traps, since they tend to lure in more beetles than they ever catch.
Fix:
- Hand-pick beetles in early morning and drop into soapy water
- Avoid pheromone traps that attract more beetles
- Treat heavy infestations with an appropriately labeled insecticide following directions
Sticky, curled shoots on the new growth
Curled, sticky new shoots usually mean aphids, and sometimes whiteflies, crowding onto the tenderest growth and leaving a sugary honeydew that can darken with sooty mold. A firm jet of water knocks most of them off, and a follow-up with insecticidal soap handles the stragglers. If you can be patient, lady beetles and other helpful predators often mop up the rest for you.
Fix:
- Dislodge aphids with a strong spray of water
- Apply insecticidal soap or horticultural oil to affected growth
- Encourage natural predators such as lady beetles
Flower buds yellowing and dropping early
When buds turn yellow and fall before they open, that is bud drop, and it almost always traces back to a dry spell or uneven watering rather than any disease. The plant itself is perfectly healthy; it just lets buds go when the root zone keeps swinging between wet and dry. Keep the soil evenly moist through bud set and the hottest weeks, lay down a little mulch to hold that moisture steady, and the problem eases.
Fix:
- Maintain even soil moisture, especially during bud set and hot weather
- Mulch to conserve moisture and buffer soil temperature
- Avoid letting the root zone dry out completely while flowering
Spotted, blotchy leaves and a cankered stem or two
A few fungal leaf spots, blights, and rusts can mottle the foliage, and canker fungi may now and then sink a lesion into a stem. Wet weather and crowded, still air are what make it worse, so the cure is mostly about airflow. Strip off the marked leaves, prune out any cankered wood, and open the plant up so breezes move through and the foliage dries quickly.
Fix:
- Remove and dispose of affected leaves and prune out cankered stems
- Improve air circulation and avoid overhead watering
- Apply a labeled fungicide only if problems are severe
Toxicity
If a curious pet or a small child shares the garden, you can relax completely here. Rose of Sharon is non-toxic across the board, listed by the ASPCA as safe for cats, dogs, and horses, and its flowers are even edible for people. You can plant it wherever you like without a moment of worry.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Cats are perfectly safe around it, and the worst a nibbled leaf or flower might bring is a brief tummy upset from the roughage, nothing more.
Dogs None
Since the ASPCA lists it as non-toxic to dogs, a curious chew here is no cause for alarm.
Horses None
Horses are in the clear as well, and nibbling a few leaves in passing carries no special risk for them.
Rabbits Safe
Rabbits can browse the leaves without harm, though as always it is kind to introduce any new food a little at a time.
Livestock Safe
There are no worrying toxins here for cattle, goats, or sheep that happen to wander past a planting.
Birds Safe
Backyard and wild birds are safe around the shrub, and many will stop by the flowers for a sip of nectar.
People Safe
People are safe too, and the flowers are actually edible, lovely eaten raw in a salad or steeped into a gentle tea.
No special handling precautions for toxicity; as with any plant, ingestion of large amounts of plant material may cause mild, transient stomach upset.
Varieties
Growers have coaxed a lovely range of colors and flower shapes out of this one shrub, from clean single blooms to soft, ruffled doubles. Any of the named selections below is a friendly place to begin.
Diana
Diana offers pure white single flowers that linger open into the evening, and being a sterile triploid it sets almost no seed.
Blue Bird (Oiseau Bleu)
Blue Bird, also sold as Oiseau Bleu, wins hearts with big single flowers in a true violet-blue, each one centered on a red eye.
Minerva
Minerva brings soft lavender-pink blooms marked by a reddish-purple eye deep in the throat.
Aphrodite
Aphrodite shows off dark pink single flowers set around a deep red center.
Red Heart
Red Heart pairs crisp white petals with a bold red center for a clean, cheerful look.
Lavender Chiffon
Lavender Chiffon opens lavender semi-double, anemone-form flowers finished with an extra ruffle of inner petals.
How to propagate
Making more plants is easier than you might expect, and the method you choose simply decides whether the new plant looks like its parent. Cuttings and layering keep the flower color true to the original, while seed is a happy gamble if you do not mind a surprise in the results.
Stem cuttingsEasy
Softwood cuttings in late spring to summer; hardwood cuttings in late fall to winter · Several weeks to root; transplantable the following season
Cuttings are the surest way to copy a plant you love, because they keep the parent's exact flower color. Take softwood cuttings in late spring or summer, or hardwood cuttings from late fall into winter, and they will root over several weeks. Grow them along and they will be ready to move to their new home the following season.
SeedEasy
Sow late winter to early spring; the species also self-seeds outdoors · Germinates in a few weeks; flowers in 2-3 years
Seed is easy to try but asks for patience, and the seedlings rarely match the parent's flower color. Sow from late winter to early spring and the seeds sprout within a few weeks, though a young plant needs 2 to 3 years before it flowers. The shrub also self-seeds freely outdoors, sometimes more freely than you would wish.
LayeringEasy
Spring to summer · One growing season to root before separating
Layering is the gentlest, most hands-off route of all. Bend a low branch down to the soil in spring or summer, pin it in place, and it will grow its own roots over a single season before you snip it free as a brand new plant.
Myths
Rose of Sharon poses a poisoning risk to dogs and cats.
You can set this fear aside. The ASPCA lists Hibiscus syriacus as non-toxic to dogs, cats, and horses, so a pet that samples a leaf or flower is in no danger at all, and the flowers are even edible for people. The most you might ever see is a passing upset stomach from eating a large amount of any plant.
Pruning Rose of Sharon in summer or fall gives you more flowers.
It is an easy mistake to make, but it works the other way around. The shrub blooms on new wood, the growth it makes in the current season, so a summer or fall cut removes the very stems that were about to flower. Prune in late winter or early spring before growth begins, and if you cut back to 2 or 3 buds you trade a little quantity for noticeably larger blooms.