Gardeners' Dirt: Rose mallows add large, showy flowers to landscape
By Roy Cook - Victoria County Master GardenerEdited by Charla Borchers Leon
May 10, 2012 at 12:10 a.m.
Hibiscus is a genus of flowering plants in the mallow family, malvaceae. It is a large family with several hundred species, native to warm-temperate, tropical and subtropical regions throughout the world.
Some of the many closely related and similar in-appearance, ornamental plants in the family are hollyhocks (alcea), mallows (malva and kosteletzkya species), such as seashore mallow and common mallow, Turk's cap, okra and the cotton plant. They may be related and even look alike in foliage and bloom, but each has its own characteristics and growing patterns.
Some hibiscus are hardy perennials. Others are shrubs or tropical plants and some are annuals. Less known is the genus rose mallow, noted for large, showy flowers.• Flowers to 12 inches - Tough, hardy shrubs light up gardens with flowers up to 12 inches across. The hardy hibiscus hybrids are a part of a group of plants called hibiscus, rose mallow, rose of Sharon, althea, swamp mallow and giant mallow, among others. No matter what they are called, these are mid-size shrubs, hybridized from some of the most beautiful North American wildflowers.
• Tropical vs. Non-tropical - The genus hibiscus has tropical and non-tropical species. For purposes of this article, I am referring to non-tropicals. The tropical with smaller flowers is hibiscus rosa-sinensis or China rose, which is the state flower of Hawaii and national flower of Malaysia.
Easy to grow
Hardy hybrids are yard shrubs that are winter hardy. They will die back in the winter and come back in the spring if properly mulched. Be patient. • Leaf out in spring - In late spring, they will leaf out, so don't think they are dead and chop them down. All they need is full sun and moderately productive soil with plenty of organic matter (they will sometimes adapt to poor soils). Plenty of water is necessary for abundant blooming. Water plants deeply and thoroughly.
• Need wind block - Tall plants should be located where they are not exposed to strong winds to keep from breaking the long stems. Broken stems can be cut back and new side shoots will grow, producing more blooms. To encourage blooming, remove old blooms before they start forming seed heads.
Species and cultivars
There are many species and cultivated varieties, so I will just mention some of the most common and popular ones. • Scarlet Rose Mallow (hibiscus coccineus) - Southeastern native also commonly known as Texas Star Hibiscus. It is native to marsh-like habitats, so it requires a lot of water. It dies back in the winter, but returns in the spring. There is also a white-flowering variety known as the White Texas Star or Lone Star Hibiscus. These two plants can be started from seed in early spring.
Confederate Rose or Cotton Rose Mallow (hibiscus mutabilis ) - A plant noted for its double flowers that open white or pink and change to deep red by evening. Large shrubs from 8 to 15 feet are grown as tall perennials. • Lady Baltimore - Popular old variety with pink flowers and red centers. Grows to 5 feet tall with deeply cut, dark green leaves.
• Lord Baltimore - Old variety, known as dinner plate hibiscus, with deeply cut foliage and red flowers on 5-foot plants.
• Moy Grande - A newer hybrid bred in San Antonio with extra large flowers up to 12-inches wide. Plants grow 5-feet tall.
Southern Belle Mix - Red, pink and white flowers to eight inches across. Grow to five feet tall. Can be grown from seed. Available online or through mail order catalog.
Disco Belle Mix - Colors from white to dark red. Parasol-shaped flowers up to ten inches across from plant about three feet tall. Can be grown from seed. Also known as frisbee hibiscus. Available online or through mail order catalog.
Kopper King - A unique variety with copper-red, deeply cut leaves. The 12-inch wide flowers are light pink to white with burgundy center.
Some garden centers and nurseries carry rose mallows seasonally, but you should not expect them year-round. Call around or visit locations particularly this time of year for availability May through August.
If you have a friend or neighbor that grows rose mallows, be nice to them. They might let you have some cuttings - and they propagate easily.
Go online to find out how to propagate the variety you are interested in. You can also go online to find out how many varieties can be grown. You might find one you are interested in. They are plants that will add large, showy flowers to your landscape.
The Gardeners' Dirt is written by members of the Victoria County Master Gardener Association, an educational outreach of Texas AgriLife Extension - Victoria County. Mail your questions in care of the Advocate, P.O. Box 1518, Victoria, TX 77901; or firstname.lastname@example.org, or comment on this column at VictoriaAdvocate.com.