Hello,
I live in Richmond Hill, Ontario.
Can I grow a hibiscus plant outside? If so, which variety would be the best and where can I purchase it?
Thank you, Lina.
Thank you for contacting Toronto Master Gardeners.
The genus Hibiscus is in the mallow family (Malvaceae) and includes several species that are native to warm temperate, subtropical and tropical regions throughout the world. We present here the 3 most common species we encounter in the Toronto area: tropical hibiscus (usually Hibiscus rosa sinensis), hardy hibiscus (Hibiscus moscheutos) and Rose of Sharon (Hibiscus syriacus).
Hibiscus rosa-sinensis commonly known as tropical hibiscus is a woody, evergreen shrub or small tree. It bears 4- to 6-inch blossoms all summer. Solitary, five-petaled flowers 4 inches across range from single to ruffled and double. Colors include yellow, orange, pink, red, and combinations.
This hibiscus is considered a tropical houseplant in our area. It can be grown outside in a container over the summer. It will require at least 6 hours of sunlight and daily watering over the summer. It will flower best in temperatures between 16 to 32C. Fertilize with a high potassium fertilizer about once a week over the summer months. It will need to be moved inside during fall and winter months.
Here are some helpful articles for care of tropical hibiscus:
- https://hortchat.com/info/tropical-hibiscus
- https://www.finegardening.com/plant/chinese-hibiscus-hibiscus-rosa-sinensis
- https://www.torontomastergardeners.ca/askagardener/winterizing-hibiscus/
Hibiscus moscheutos commonly called hardy hibiscus or swamp rose mallow hibiscus is a perennial native to North America. Each year it will send up new stems and will die back to the ground in winter. It thrives in moist and slightly alkaline soil and blooms from July to September. Keeping rose mallow well-watered will help to encourage flowering. The flowers grow on new wood – that’s why pruning down your hibiscus in the fall or spring and continuing to dead head through the summer will provide you with many flowers through the growing season. If all the growing conditions are met you should have a 3-6ft bush by the end of the season.
For further reading please see the following links:
- https://www.torontogardens.com/2016/08/enormous-hardy-hibiscus-is-not-a-pest.html/
- https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=b492
- https://www.finegardening.com/plant/common-rose-mallow-hibiscus-moscheutos-and-cvs
Hibiscus syriacus commonly called Rose of Sharon or shrub althea, is a vigorous, upright, vase-shaped, multi-stemmed, deciduous shrub that typically grows 8-12’ tall. This is another which will survive our winters. Rose of Sharon will produce many flowers throughout the summer. These plants do best in a sunny site with moist, but well-draining soil.
The following article is an excellent resource:
Toronto Master Gardeners are not in the practice of suggesting vendors or services. Many of the larger Toronto area nurseries have websites with a plant search function which will show you the plants they carry, so a few minutes online may save you some phone calls. A look at the Landscape Ontario site can pinpoint the nurseries closest to you; you can narrow down your search from there. Here is their website, https://landscapeontario.com/find-a-company (just click on the garden center tab).
Good luck!