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Hibiscus

Hibiscus is a large genus of flowering plants in the Malvaceae or mallow family. The Malvaceae family includes many plants grown for their ornamental flowers and vegetable and fiber plants, such as okra and cotton. Perennial and annual hibiscus and other closely related members of the mallow family are grown as ornamentals in South Carolina.

Perennial and annual hibiscus are grown as ornamentals in South Carolina. Barbara H. Smith, ©2023 HGIC, Clemson Extension

Perennial and annual hibiscus are grown as ornamentals in South Carolina.
Barbara H. Smith, ©2023 HGIC, Clemson Extension

Perennial Hibiscus

Mature Height/Spread: While dwarf varieties may only grow two to three feet tall, many varieties and species can attain heights of eight feet or more each growing season once established. Young plants are generally narrower than tall, but mature clumps often spread as wide as their height.

Growth Rate: Perennial hibiscus generally reach their mature height within two or three years and return to that height each year. Best growth occurs when plants have ample moisture. Many hardy hibiscus can bloom the first year from seed started in early spring.

Ornamental Features: Hibiscus are grown primarily for their strikingly beautiful and often amazingly large flowers. The foliage is often bold and remarkable but is less noticeable in the mid to late summer when blossoms are so prominent. Hibiscus give a bold, tropical effect to a garden. They are also highly attractive to butterflies and hummingbirds.

Culture: Many perennial hibiscus are natives of South Carolina and the Southeastern US. They prefer a sunny location and well-drained soil that contains plenty of organic matter. Hibiscus will tolerate light shade and less desirable soils, but their vigor and flowering will be reduced. Plenty of water is necessary for the most abundant blooming. Newly planted hibiscus will need more frequent watering, similar to other newly planted perennials. Water needs vary by species and variety, with some species and varieties tolerating permanently damp soil and flooding.

Tall hibiscus should be planted without exposure to strong winds to avoid breaking the long stems. Stems that break can be shortened, allowing new side shoots to grow and produce more blooms.

To encourage reblooming, remove old flowers before they form seedheads or prune plants back by one-third after a flush of bloom is finished.

Perennial hibiscus will freeze back to the ground each winter in all but the warmest parts of South Carolina. When new growth emerges in the early spring, old stems can be cut back to the ground.

Propagation: Hibiscus are easy to propagate by several methods, making them a common “pass-along” plant, especially since some popular types, such as Cotton Rose Mallow (also commonly known as Confederate Rose), can be difficult to find in stores.

Cuttings: Cuttings can be rooted when new growth is available, although rooting is usually quickest in spring. Start with a pencil-thick, five- to six-inch-long cutting of firm new growth. Strip off lower leaves and insert the cutting in a mix of three parts sand and one part peat. Roots should form within four to five weeks. Once roots are formed, plants can be moved into a larger container or transplanted to a permanent location.

Seeds: Seed can be sown indoors 12 weeks before the last spring frost. Soak seeds overnight before sowing. Seed can also be sown in place outdoors after the last expected frost date, or fresh seed can be sown in the fall. Collect seed for fall sowing once the papery seed capsules brown and start to split. Plants may bloom from seed in their first year and often self-seed in suitable soil conditions.

Division: Perennial hibiscus can be divided in spring. Be careful working around the soft new shoots. They do not usually tolerate fall division or transplanting.

Problems: Leaf spots may be caused by several fungi. In most cases, cleaning up plant debris and removing infected leaves will provide adequate control. Southern stem blight may occur on hibiscus. To help prevent southern blight, keep mulch from touching the stems.

Insect pests of hibiscus include aphids, whiteflies, and Japanese beetles. For more information on insect control, please see HGIC 2770, Less Toxic Insecticides and Japanese Beetles.

Species & Cultivars

Scarlet Rose Mallow (Hibiscus coccineus): Also known as Texas Star Hibiscus, this species is native to portions of the Southeast and hardy in USDA Zones 6-9. The six- to eight-inch-wide flowers are brilliant red, with petals more separated than those of other hibiscus, giving the blossom a star-shaped look. Individual flowers last only a day, but new blooms open throughout summer and fall. The leaves are deeply divided into narrow, toothed, finger-like lobes. This plant is often passed along from gardener to gardener.

The showy red flowers of Scarlet Rose Mallow (Hibiscus coccineus) are attractive to hummingbirds, butterflies, and other pollinators.

The showy red flowers of Scarlet Rose Mallow (Hibiscus coccineus) are attractive to hummingbirds, butterflies, and other pollinators.
Terasa Lott, ©2023, Clemson Extension

Scarlet Rosemallow leaves are deeply divided into narrow, toothed, finger-like lobes.

Scarlet Rosemallow leaves are deeply divided into narrow, toothed, finger-like lobes.
Barbara H. Smith, ©2024 HGIC, Clemson Extension

Scarlet Rose Mallow will often self-seed from seeds produced in the fall.

Scarlet Rose Mallow will often self-seed from seeds produced in the fall.
Barbara H. Smith, ©2023 HGIC, Clemson Extension

Established plants grow to seven feet each growing season. Plants die back to ground level in winter and resprout in spring.

Scarlet rose mallow prefers full sun and moist soil. Naturally occurring in swamps, marshes, and ditches, this hibiscus will tolerate some flooding, although it will also tolerate somewhat drier conditions common in the home garden.

Divide plants in the spring. Plants often self-seed from seeds produced in the fall.

Rose Mallow (Hibiscus moscheutos): Rose Mallow is a Southeastern native that grows in marshes, wet meadows, swampy forests, and wet ditches. It is hardy in USDA Zones 4-9. It has been extensively bred and is the parent of several popular hibiscus hybrids, often referred to as dinner plate hibiscus due to the large size of their flowers. The large, fast-growing plants bloom from August to October. Individual flowers last only a day, but each plant may flaunt several 7- to 12-inch-wide flowers at once, which are attractive to butterflies and other pollinators.

Grow rose mallow in rich, well-drained soil with full sun for best results. Cut old stems back to three to six inches above ground level in late winter or early spring.

Propagation is possible by seed, tip cuttings, and root division. Rose mallow will flower from seed the first year if started very early in spring. Cuttings can be rooted during the growing season.

Rose Mallow (Hibiscus moscheutos) is highly variable and the parent to many hybrids.

Rose Mallow (Hibiscus moscheutos) is highly variable and the parent to many hybrids.
Barbara H. Smith, ©2023 HGIC, Clemson Extension

Cultivars

  • ‘Anne Arundel’ has nine-inch diameter pink flowers, and the plants can grow to five feet tall.
  • Disco Belle® series – This series boasts compact plants topping out at three to four feet with large flowers ranging from white with a red eye to all red.
  • ‘Kopper King’ is unique for its coppery red deeply cut leaves. The 12-inch-wide flowers are light pink to white with a burgundy center. It may not be fully hardy in the Upstate.

Head Over Heels® Adore™ Hibiscus (Hibiscus moscheutos ‘RutHib3’) is in the Disco Belle® series.

Head Over Heels® Adore™ Hibiscus (Hibiscus moscheutos ‘RutHib3’) is in the Disco Belle® series.
Barbara H. Smith, ©2023 HGIC, Clemson Extension

Kopper King Hibiscus (Hibiscus moscheutos ‘Kopper King’) has copper red deeply cut foliage.

Kopper King Hibiscus (Hibiscus moscheutos ‘Kopper King’) has copper red deeply cut foliage.
Karen Russ, ©2007 HGIC, Clemson Extension

  • ‘Lady Baltimore’ is a popular old variety sporting pink flowers with red centers. Plants grow to five feet tall with deeply cut, dark green leaves.
  • ‘Lord Baltimore’ is another old variety with crimson-red flowers on five-foot-tall plants. Leaves are even darker and more deeply cut than those of ‘Lady Baltimore.’
  • Summerific® series – This hybrid series contains at least a dozen cultivars ranging in height from three to four and a half feet with a number of color options. Flowers range from seven to nine inches.
Cotton Rose Mallow (Hibiscus mutabilis) is an old favorite passalong plant.

Cotton Rose Mallow (Hibiscus mutabilis) is an old favorite passalong plant.
Barbara H. Smith, ©2023 HGIC, Clemson Extension

Cotton Rose Mallow (Hibiscus mutabilis): Cotton Rose Mallow (also commonly known as Confederate Rose) is a large shrub that behaves as a perennial in most of the state, dying back in the winter and regrowing each spring from the base. It is hardy in USDA Zones 7-9. It may behave as a deciduous shrub in warmer coastal areas, leafing out on old stems. Although the common name implies connections to the South, Confederate Rose is native to China and Taiwan.

Cotton Rose Mallow will grow in full sun to partial shade. It prefers loamy, well-drained soil but is tolerant of many soil conditions. Plant height varies from about eight feet in the Upstate to 15 feet on the coast. With the exception of the Piedmont of South Carolina, rejuvenation pruning can be utilized if plants become leggy.

The specific epithet mutabilis refers to the change in flower color that occurs. Flowers of the species are white when they first open and darken as they mature. Varieties are available with single or double flower forms that range in color from white to pink to red.

Cuttings can be taken almost any time, but spring will likely result in the highest success. Due to the ease of propagation from cuttings, it is often passed from one person to another.

Swamp Rose Mallow (Hibiscus grandiflorus): Swamp Rose Mallow is a tall perennial wetland plant with large showy flowers and green, velvety leaves. Sometimes found in brackish conditions, it can be grown where other plants succumb to salty conditions. It is hardy in USDA Zones 8-11.

Rose Of Sharon (Hibiscus syriacus): Also known as Althea, this native of China and Taiwan is a durable deciduous shrub that grows 8 to 10 feet tall and 6 to 10 feet wide. It is hardy in USDA Zones 5-9. Flowers appear during the hottest months. A wide variety of cultivars are available, with flowers in various colors and forms. Be aware that some cultivars will readily produce offspring from seed.

Rose of Sharon (Hibiscus syriacus) is a native of China and Asia.

Rose of Sharon (Hibiscus syriacus) is a native of China and Asia.
Barbara H. Smith, ©2023 HGIC, Clemson Extension

Purple Pillar® Rose of Sharon (Hibiscus syriacus 'Gandini Santiago' ) has ruffled lavender semi-double blooms with dark red centers.

Purple Pillar® Rose of Sharon (Hibiscus syriacus ‘Gandini Santiago’ ) has ruffled lavender semi-double blooms with dark red centers.
Ginger Long, ©2023 HGIC, Clemson Extension

Annual Hibiscus

Chinese Hibiscus (Hibiscus rosa-sinensis) has four- to eight-inch single or double flowers that are available in a wide range of colors.

Chinese Hibiscus (Hibiscus rosa-sinensis) has four- to eight-inch single or double flowers that are available in a wide range of colors.
Barbara H. Smith, ©2023 HGIC, Clemson Extension

Chinese red-leaf hibiscus are tropical shrubs commonly grown as annuals in South Carolina.

Chinese Hibiscus (Hibiscus rosa-sinensis): This tropical shrub is a vigorous grower with magnificent flowers. Native to Asia, it is only hardy in the small area along the coast of South Carolina designated as Zone 9 (a and b). For this reason, it is generally used as a summer annual but can also be grown as a houseplant.

Cranberry Hibiscus (Hibiscus acetosella) is a tropical shrub that is grown for its beautiful burgundy foliage.

Cranberry Hibiscus (Hibiscus acetosella) is a tropical shrub that is grown for its beautiful burgundy foliage.
Barbara H. Smith, ©2023 HGIC, Clemson Extension

The flowers are available in many colors, ranging through nearly the entire spectrum. The yellow, apricot and orange varieties provide colors not seen in hardy perennial hibiscus. Flowers are typically four to eight inches wide and may be single or double.

When overwintering, move Chinese hibiscus outside after all danger of frost has passed. Be sure to acclimate plants gradually to the increased light and lower temperatures outside. They prefer rich, well-drained soil with plenty of organic matter and full sun or light afternoon shade. Water the plants freely during the growing season. To keep mature plants growing vigorously, prune old wood back by about one-third in spring. Bring Chinese hibiscus indoors when nighttime temperatures fall into the lower 50s °F.

Cranberry Hibiscus (Hibiscus acetosella): Sometimes called African rose mallow, this hibiscus is a tropical shrub, usually grown as an annual for the beauty of its foliage rather than its flower. It typically grows 3 to 5 feet tall and about 2.5 feet wide. Small crimson to purple flowers may appear late in the growing season. Plant outside after the danger of spring frost has passed, in full sun and well-drained, moist garden soil. Like Chinese hibiscus, plants are only hardy in USDA Zone 9. Plants can be overwintered indoors. Propagation is mainly through seed planted in the spring.

Related Plants

There are many ornamental plants closely related and similar in appearance to hibiscus. These include hollyhocks (Alcea) and mallows (Malva and Kosteletzkya species).

Hollyhocks (Alcea rosea) are one of the most popular old-fashioned cottage garden flowers.

Hollyhocks (Alcea rosea) are one of the most popular old-fashioned cottage garden flowers.
Barbara H. Smith, ©2023 HGIC, Clemson Extension

Hollyhock (Alcea rosea): Hollyhock is one of the most popular old-fashioned cottage garden flowers, with a distinctive upright pillar of large, brightly colored blooms for a few short weeks in summer. Hollyhocks are biennials, with young plants appearing from seed in late summer or fall and blooming the following summer.

Plants typically grow from three to six feet tall, but eight-foot-tall giants are not unusual, especially if grown in rich, well-drained soil with ample moisture. Flowers range from three to five inches wide and come in a full spectrum of colors.

Hollyhock rust is the main problem affecting these plants. Removing infected leaves and cleaning out old plant debris will help prevent over-wintering spores from infesting next year’s plants. Newer cultivars are less susceptible to rust.

Plant hollyhocks from seeds or plants after the threat of frost has passed. If using seed that has been collected, sow it as soon as the seed is ripe.

Turk's Cap (Malvaviscus arboreus var drummondii) has bright red flowers that are attractive to butterflies and hummingbirds.

Turk’s Cap (Malvaviscus arboreus var drummondii) has bright red flowers that are attractive to butterflies and hummingbirds.
Barbara H. Smith, ©2023 HGIC, Clemson Extension

Virginia Saltmarsh Mallow (Kosteletzkya virginica): This perennial hibiscus is native to salty or brackish marshes all along the eastern seaboard and across to Texas. It is a useful plant near the beach but will thrive in ordinary garden soil if given adequate irrigation. Plant it in full sun.

Small, 2½-inch-wide lavender-pink blossoms appear in abundance from June through October. The variety ‘Immaculate’ bears pure white flowers. Plants grow three to six feet tall depending on the amount of soil moisture.

Turk’s Cap (Malvaviscus arboreus var drummondii): This botanical variety is native to portions of the Southeast, while other varieties of the species are not. This perennial is grown for its constant blooms that resemble a Turkish turban. The bright red, three-inch-long hibiscus-like flowers never fully open and have long, protruding stamens. It is hardy in USDA Zones 8-10. Turk’s Cap can easily be planted from cuttings or seed but is not frequently found in nurseries. Attractive to butterflies and hummingbirds, it is usually passed along from gardener to gardener.

Originally published 12/04

If this document didn’t answer your questions, please contact HGIC at hgic@clemson.edu or 1-888-656-9988.

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