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Pruning guide · Shrub
Rose of Sharon (hardy hibiscus): when and how to prune
Hibiscus syriacus
Prune a rose of Sharon at the end of winter, in March: shorten last year’s shoots to 2–3 buds for larger flowers, or only remove dead and crossing branches for a natural shape.
The rose of Sharon, or hardy hibiscus, is a shrub of 2–3 m that flowers when most shrubs have finished, from August to October. It flowers on new wood: the flowers come on the shoots that grow in spring and summer. That is why you prune it at the end of winter, giving it the whole season to make flowering shoots. How hard you prune decides the shape: cutting back short gives fewer but larger flowers, light pruning a natural shrub full of smaller flowers.
| Pruning months | March |
|---|---|
| Nesting season (15 March–15 August) | Take care in March |
| Flowering | August–September |
| Good for bees, butterflies and birds | Yes, for bees |
| Native to Belgium | No, planted |
Rose of Sharon (hardy hibiscus): when to prune it?
Prune at the end of winter, in March, before it comes into leaf.
Don’t prune too late in spring: it is already late to leaf up, often not until May, and needs the whole season to make new shoots with flower buds.
If it looks dead in April, calmly wait until the end of May before cutting anything off: scratch a twig, and if it is green under the bark, it is alive.
What else to prune in those months? March
Rose of Sharon (hardy hibiscus): how to prune it?
- For large flowers: cut all of last year’s shoots back to 2–3 buds above the older wood.
- For a natural shape: prune lightly, and only remove dead, weak and crossing branches.
- Every few years, saw one of the oldest branches off at the base, so the shrub renews itself.
- Keep a standard in shape by shortening the head into a compact ball every March, and removing shoots on the trunk and at the base.
- An old shrub that has grown out of shape copes with hard pruning in March, back to a framework of thick branches. It then flowers a little later and less that year.
How much to cut, and how often?
- Cutting back short or pruning lightly: both are fine, every year in March. Choose what you like best.
- An old shrub: every few years an old branch at the base.
What does it mean for wildlife?
- March falls mostly before the nesting season (from 15 March). If you are late, first check that no birds are starting to nest in the shrub.
- In August–October, when little else is flowering, bumblebees and bees crawl deep into the large trumpet flowers. Single-flowered varieties are best for insects.
- Aphids on the young shoots in early summer feed ladybirds, hoverfly larvae and tits: don’t spray.
- In a warm garden it sometimes self-seeds. Pull up the seedlings if you don’t want them.
Common mistakes
- Pruning in May, so the flowering is late and sparse.
- Taking a shrub that is still bare in April for dead and throwing it away.
- Clipping it all over like a hedge every year, so it forms a broom of thin twigs.
- Leaving the trunk shoots after hard pruning, so the standard turns into a shrub.
Caution: Don’t prune too late in spring: it needs the whole season to grow new shoots that carry flower buds.
Nearby: related pruning guides
Plant profile: Rose of Sharon (hardy hibiscus) · Pruning calendar and basic rules