Since Mother Nature refuses to provide us with a peek at Spring, we’ll take a wishful look at growing tropical hibiscus. Picture glossy green leaved shrubs, trimmed to five or six feet high, forming a privacy screen around a red brick patio. Sprinkled among the leaves are beautiful large blooms in shades of bright yellow and red, as well as coral, pink and even bi-colors. These showy blooms can appear in nearly every shade except blue and near-black. Some of the 2 -3 inch flowers are “doubles,” giving them a feminine ruffled look. All have a prominent style and stigma pads, with colorful pollen sacs adding to their overall beauty. What pollinator could resist! The flowers bloom for a single day.
The tropical hibiscus, the national flower of Malaysia and the state flower of Hawaii, is a member of the Malvaceae or mallow family. Its relatives, which grow well in Wisconsin include hardy hibiscus and hollyhocks. The plant originated in the Asian and Pacific islands, but interest in this shrub traveled to Florida where the American Hibiscus Society was founded in 1950.
While tropical hibiscus cannot over-winter in Wisconsin outdoors, it is a great plant for pots. Planting in pots allow you to choose just the right location where it can receive bright light with a bit of shade to promote more blooms. Used to the heat and bright sun of Florida, it can tolerate the sun on south facing deck or porch. However, maintain even moisture because buds may drop from over- or under-watering; good draining soil is a must. Insect pests such as aphids and thrips may also contribute to bud drop, so watch for them and treat the plant, if necessary. Another sign of stress may be yellowing leaves with leaf drop. Yellow leaf drop is common when bringing the potted plants indoors for the winter, which is recommended at the first hint of frost, which tropical hibiscus cannot tolerate. Temperatures between 35 and 40 degrees for a few hours may also contribute to plant damage.
Despite some of the challenges of growing hibiscus in Wisconsin’s climate, the potted tropical hibiscus can last for more than ten years so you may consider getting one started this summer to make next winter feel a bit warmer.
To learn more about hibiscus varieties visit the American Hibiscus Society for tropical growers and which includes some guidance for growing hibiscus in the north:
The Wisconsin Master Gardener website includes several articles on hibiscus varieties for our climate including this stunning specimen: