Top 10 Questions About Rose of Sharon

Plants with deceptive names carry an air of mystery that please some gardeners and annoy others. I, for one, love the fact that Rose of Sharon (Hibiscus syriacus) is neither a member of the rose family nor native to Syria. That means it's not just a hardy hibiscus, but a plant with secrets. And you can't beat those papery flowers that keep on coming just when we need them most!

Rose of Sharon plants aren't tricky in their cultural requirements, but issues do come up. Here at Gardening Know How we do get some questions about these plants and love to help out. Here are the 10 most commonly asked questions about planting and caring for Rose of Sharon, so if your hibiscus isn't thriving, you might be able to find the solution.

1. How and when to plant a Rose of Sharon shrub?

Ready to invite a Rose of Sharon shrub into your garden? The best time to transplant is fall. These are deciduous plants that lose their leaves in winter, but transplanting in fall, together with autumn rain, allows those roots to dig in well before the dead of winter.

2. Why won't my Rose of Sharon buds open?

What's more disappointing than to have a hibiscus bush full of buds that just won't open? Happily, the cause of this is usually cultural, which means an issue you can resolve. Rose of Sharon shrubs grow best in full sun. A too-shady location may work for younger shrubs, but too much shade can cause fungal issues and failure to flower in older plants. Irrigation can be an issue as well. Too much water can cause bud rot, while too little can also stifle flowering.

3. How and when to move Rose of Sharon shrubs/trees?

Rose of Sharon shrubs transplant without much fuss, so consider this for shrubs in the shade. When the plant is dormant, dig out its root ball including a couple of feet of soil, carry it to a new (sunnier) location, then water well. It will send down roots and regenerate in spring.

4. When should you prune a Rose of Sharon?

These hibiscus shrubs bud and flower on new growth. That means that the ideal time to prune a Rose of Sharon plant is soon after the blossoms have faded.

5. Do you need to deadhead Rose of Sharon blooms?

We adore these shrubs for their pleasing papery blossoms, but their easy-going ways are also extremely appealing. Hibiscus, in general, and Rose of Sharon, in particular, are self-cleaning and do not require deadheading. On the other hand, deadheading can reduce unwanted seedlings.

6. My Rose of Sharon isn't leafing out. Why?

Every plant has its own particular limits in terms of temperature. Generally, Rose of Sharon shrubs thrive down to USDA hardiness zone 5, so if your zone is lower, your winter cold may kill off these shrubs. Even in zone 5 you may see winter damage. Sometimes, these plants are simply slow to leaf out, as they prefer warmer temps to do so. Patience is a virtue here. That said, you can do the scratch test just to be sure. Scrape off some bark to determine whether the stems are alive - green means yes, brown means no. If they are green, cut them back and see if they develop new growth.

7. Where are the seeds on Rose of Sharon plants and how to propagate them?

It always feels a little like magic to replant a shrub from its own seeds. Look for lobed seed pods that develop after the blossoms fade. Each lobe holds at least three seeds. These seeds grow readily in moist, well-drained soil. In fact, you may get more seedlings than you want just under the bush, and these can be transplanted to a new bed.

8. Why are my Rose of Sharon leaves turning yellow and dropping?

Try to remember the morning after your last big move, how strange it felt to be in a new location. That's the human equivalent of transplant shock. Recently transplanted shrubs may be feeling that shock which can cause dropping leaves or yellowing leaves. Water new transplants every few days for a while, then irrigate at least every week for the growing season.

9. How do I get rid of or control Rose of Sharon seedlings?

I try to think of this as a form of divine justice: easy-care plants are often the ones that overrun the garden, spreading new seedlings far and wide. Rose of Sharon plants do seed easily and there's no getting around the need for regular removal. Your best bet to control them is to hand-pull early and often and, for heaven's sake, don't put the seedlings anywhere near the compost.

10. How can I start new Rose of Sharon plant cuttings?

You'll find it remarkably easy to start new Rose of Sharon from softwood cuttings taken in spring. Remove all but the top set of leaves, then trim the cutting just under a leaf node. Put into moist, well-draining soil and cover with a plastic bag to hold in the moisture.

We all have questions now and then, whether long-time gardeners or those just starting out. So, if you have a gardening question, get a gardening answer. We're always here to help.

Teo Spengler

Teo Spengler has been gardening for 30 years. She is a docent at the San Francisco Botanical Garden. Her passion is trees, 250 of which she has planted on her land in France.