Hibiscus belongs to the mallow family along with its cousins, althea, cotton, hollyhock, okra and Turk’s cap. One group within the genus Hibiscus immediately attracts attention with the size of each individual flower. These are known as perennial or rose mallow hibiscus. My great-grandmother Flossie Wallace in rural Shelby County called them “dish pan” hibiscus because the flowers were so large. Rose mallow hibiscus come in many colors and sizes and are cold-hardy perennials as opposed to the beautiful tropical hibiscus we have to grow in pots and protect.
Among the numerous cultivars available, there is considerable variation in the shape, size and texture of the foliage and in height of growth produced each year. Their colors also vary from white through pink to red. There are even some with burgundy foliage now. They are all descendants of the native hibiscus found in East Texas, Louisiana, and other Deep South states. When hybrids of these first appeared many years ago, they were sold as “Mallow Marvels.” Because of the size of their flowers and their continuing display of summer color, they are still a marvel to me and are among the most spectacular and easily grown plants.
Perennial hibiscus prefers a sunny location and well drained soil containing plenty of organic matter and nutrients. Rich, moist soil and full sun promote the most vigorous growth, but mallows are very accommodating and will tolerate light shade and less desirable soils as well. To bloom and grow profusely, hibiscus must have enough water. Many, like their marsh growing parents, will actually tolerate flooding. As with most other plants, watering should be done thoroughly and not too frequently. Once a week (minus rain) during June, July, and August is plenty. Some protection from strong winds is necessary since the main stalks can occasionally be broken. If this occurs during the growing season, removal of the broken section will stimulate side shoots which ultimately results in more blooms.
I generally shear my rose mallow hibiscus plants with the hedge clippers several times after they emerge in the spring so they’ll be dense, full and produce more flowers. I just cut off a few inches each time. I also shear them after each bloom flush fades to tidy them up and stimulate new growth and flowers. A sprinkling of lawn fertilizer at this time helps. too.
Remember that rose mallow hibiscus are true cold-hardy perennials that die to the ground each fall and store energy in a crown with thick roots each winter. With the first frost each year, all the stems should be cut to the ground with a pair of loppers. They are typically one of the more late emerging perennials in the spring garden, but certainly worth the wait.
They are several rose mallow hibiscus designated Texas Superstars by Texas A&M including Flare, Lord Baltimore, Moy Grande and Peppermint Flare (my own introduction). These are hard to find however. Luckily, all cultivars of rose mallow hibiscus perform will in East Texas including their cousin Texas Star hibiscus (Hibiscus coccineus). If you’d like to see some of the newest cultivars available, visit plantdelights.com and go to “Hibiscus.”
(Greg Grant is the Smith County horticulturist for the Texas A&M AgriLife Extension Service. He is author of Texas Fruit and Vegetable Gardening, Heirloom Gardening in the South, and The Rose Rustlers. You can read his “Greg’s Ramblings” blog at arborgate.com, read his “In Greg’s Garden” in each issue of Texas Gardener magazine (texasgardener.com), and follow him on Facebook at “Greg Grant Gardens.” More science-based lawn and gardening information from the Texas A&M AgriLife Extension Service can be found at aggieturf.tamu.edu and aggie-horticulture.tamu.edu.)