Can you grow a rose of sharon from seeds? If so can you tell me how?
You can indeed grow rose of Sharon (Hibiscus syriacus) from seed. It’s now nearing the end of October and the rose of flowers on your plant should have developed into green seed pods by now. These will ripen after several weeks – usually early in the winter. They will turn brown and dry out, getting ready to burst and release the seeds. In order to germinate next spring, the seeds must have ripened and also need to be exposed to cold temperatures for a period (hence they ripen in winter!).
You can either pick the seedpods when they have turned light brown and store them in a cool dark place until they open to release the seeds or tie tiny nylon or paper bags over the pods while they are still on the plant, to catch the ripe seeds when the pods burst.
Store the seeds in an envelope in a cool, dry location or, if you want to hold onto them for a longer period, seal them in a jar and put this in the fridge with rice at the bottom of the jar to help prevent moisture from introducing mold and spoiling the seeds.
Before planting your seeds, it’s a good idea to first check that they are viable. Take about 10 seeds and wrap them in a damp paper towel inside a plastic bag. The seeds should start to swell, with roots emerging, in around 5-7 days.
Plant the seeds outside in spring after danger of frost has passed – plant them around 0.6 – 1.2 cm (1/4 – 1/2 inch) deep in an area that gets full sun, and seedlings should emerge later in the spring. Alternatively, start the plants indoors about 3 months before the last frost date in your area (in Toronto, last frost is around mid-May) in sterile potting mix; keep the seeds warm, in a sunny south-facing spot and the seeds should germinate in 2-4 weeks.
A suggestion: as rose of Sharon seeds usually fall close to the mother plant, it is possible that you will see little seedlings sprout on their own next spring. Look under the mother plant – you could simply transplant these seedlings to preferred locations in your garden. At the same time, consider pulling out any seedlings you don’t want – these plants can be invasive and overrun a garden!
A warning: if the mother plant is a hybrid variety, the new plants may not resemble the mother plant. Also, note that some varieties of rose of Sharon may not produce seed.
Finally, if you do go ahead and collect seeds, consider leaving a few seed pods on your rose of Sharon plant, to help feed birds over the winter.
The following references provide helpful information:
- Gardening Know How.Rose Of Sharon Seed Propagation: Harvesting And Growing Rose Of Sharon Seeds
- The Guardian. Propagating rose of Sharon. This article also discusses propagating the plant from cuttings.