By Julie Christensen
The genus Hibiscus (Hibiscus spp.) includes more than 200 species of perennials, annuals and shrubs. When you think of hibiscus, you might think of the exotic, tropical plants that are hardy only in USDA plant hardiness zones 8 through 11, but there are many other types of hibiscus. Most of them are easy-to-grow, long-lived plants.
Varieties and Types of Hibiscus
Related to okra, hollyhocks and cotton, the hibiscus family includes the Confederate rose (Hibiscus mutabilis), an old-fashioned favorite in the South that grows 8 to 10 feet tall and produces large, multi-petaled blooms that change from white to pink to red. It is hardy in USDA zones 7 to 9.
Rose of Sharon (Hibiscus syriacus) grows in zones 5 through 9, making it a suitable choice for most gardens in the U.S. Rose of Sharon is a vase-shaped shrub that grows 6 to 10 feet tall. It produces large, papery blooms in a variety of colors. Rose of Sharon blooms from mid-to-late summer, when most other flowering shrubs have lost their blooms.
Common rose mallow (Hibiscus moscheutos) grows in USDA zones 5 through 10 and is often found near swamps and marshy areas. It grows 8 feet tall and has large blooms in white, pink or red.
Chinese hibiscus (Hibiscus rosa-sinensis) is hardy only in USDA zones 9 through 11. This shrub has large, exotic flowers that come in a variety of shades, including hot pink, yellow, orange, purple, white and red. Chinese hibiscus is often grown as an annual plant in the North, or brought indoors during the winter and treated as a houseplant.
Another tropical plant treated as an annual in the U.S. is red-leaf hibiscus (Hibiscus acetosella). This plant has gorgeous reddish foliage that resemble maple leaves.
Most hibiscus plants are grown from potted nursery plants. You can also take green wood cuttings for shrub hibiscus or start annual hibiscus from seeds sown indoors 6 weeks before the last frost. Confederate rose is often called a pass-along plant because it’s easy to share through cuttings or divisions.
Regardless of the species, all hibiscus plants grow best in full sun. They need fertile, well-draining soil that stays moist, but not soggy. In most cases, you’ll only need to amend the soil with a bit of compost to improve drainage, but amend heavy clay soils with peat moss and additional compost or grow hibiscus in a raised bed.
Fertilize hibiscus plants every spring with ¼ cup 10-10-10 fertilizer. Established plants can be mulched with 3 to 4 inches of wood chip mulch to conserve moisture and prevent weed growth.
In some areas of the south, Confederate roses and other perennial hibiscus die back to the ground in the winter, eliminating the need for pruning. In more temperate climates, though, deadhead the blossoms before they go to seed. In the spring, prune the plants to remove dead and diseased limbs, old canes and branches that rub against each other. Another option is to prune back the entire plant by one-third after blooming. Don’t prune shrubs in early fall, though. Pruning stimulates new growth, which is more likely to be damaged by winter temperatures.
Hibiscus Pests and Diseases
You’re unlikely to run into many disease problems in temperate climates, but fungal leaf spots can be a problem in warm, humid areas. Remove the infected leaves promptly and clean up any debris on the ground. Use soaker hoses instead of overhead sprinklers and space the shrubs so air circulates freely.
Aphids, whiteflies and Japanese beetles can infest hibiscus, although damage is usually minor. Spray both sides of the leaves with insecticidal soap or oil to combat aphids and whiteflies. To manage Japanese beetles, handpick them and drop them in soapy water or use a pesticide labeled for treating Japanese beetles. Baits designed for Japanese beetles are largely ineffective, according to studies at the University of Kentucky, and can actually cause more damage by encouraging Japanese beetles in large numbers.
For more information on hibiscus, visit the following links:
Hibiscus from the National Gardening Association
Hibiscus from Clemson University
YouTube shows you how to prune tropical hibiscus.
Salisbury Greenhouse shows you about basic hibiscus care on YouTube.
Nutrition Facts says that hibiscus tea has the highest antioxidants of any drink.
Julie Christensen learned about gardening on her grandfather’s farm and mother’s vegetable garden in southern Idaho. Today, she lives and gardens on the high plains of Colorado. When she’s not digging in the dirt, Julie writes about food, education, parenting and gardening.