Richard C. Bogren, Owings, Allen D.
News Release Distributed 06/12/15
By Allen Owings
LSU AgCenter horticulturist
HAMMOND, La. – An abundance of hibiscus varieties do well in Louisiana.
Many of us are very familiar with the tropical hibiscuses Hibiscus rosa-sinensis. We see them frequently. They’re typically not cold-hardy for the majority of the state. They can, however, be landscape perennials in warmer areas south of interstate 10 and in slightly more northerly areas if you find a micro-climate of warm air.
The Cajun series of tropical hibiscus is popular now. They are known for their brilliant colors and petal arrangements. Other hibiscus species used in landscaping include the false roselle, rose mallows, Texas Star hibiscuses and confederate roses.
Hibiscus acetosella, commonly referred to as false roselle or African rose mallow, is a great foliage plant for summer and fall landscapes. When planted in spring, plants can easily reach heights of 5 feet or more by fall. Pruning every month or so for the first couple of months after planting produces a bushy, slightly more compact plant.
Several varieties are on the market – Mahogany Splendor, Maple Sugar, Panama Red, Haight Ashbury and Red Shield. Most of the Hibiscus acetosella have reddish foliage. Mahogany Splendor has bronzy foliage in full sun. The Haight Ashbury variety has multiple foliage shades of cream, pink and burgundy. Panama Red has deeply cut foliage that is rich carmine red.
A new variety recently developed by the U.S. Department of Agriculture-Agricultural Research Service in Poplarville, Mississippi, is Sahara Sunset. However, it is not yet available at retail garden centers.
These plants produce red flowers during short days in late fall and winter in Louisiana. But in order for this to happen, they must be protected from cold damage. Sahara Sunset needs full sun and has drought tolerance, so it needs minimum irrigation. Plants have upright growth forms and are deer-resistant. Space plants a minimum of 3 feet apart when planting.
Home gardeners should consider the white- or red-flowered Texas Star hibiscus (Hibiscus coccineaus). They are a hardy perennial, unlike the popular tropical hibiscus. Large five-petal flowers appear in early summer and continue through fall. Plants go dormant in winter and start re-growing from the roots in April. Birds, butterflies and bees are attracted to the flowers. Seed produced in pods in the late summer through fall can also be saved for later. They germinate readily.
Rose mallows are also popular in Louisiana. Some folks may know these by the name Disco Belle or dinner plate hibiscus. They are root-hardy perennials and come in an assortment of white, pink, rose and red flower colors. Huge 8-to-10-inch-diameter flowers appear in May and go through early fall.
Popular varieties include Peppermint Schnapps, Cherry Brandy and the Flare series, available in several colors. Rose mallows work well in in both well-drained or poorly drained soils with more sun than shade. Hibiscus sawflies will eat foliage of these plants – this insect can lead to unsightly foliage damage by mid-to-late summer – and can be controlled with carbaryl.
Finally, Confederate rose (Hibiscus mutabilis) is popular in south Louisiana. Plants can reach 15 to 20 feet tall. The woody stems usually do not die back during winters unless severe conditions are present. Flowers of Confederate rose begin the day as white. By early afternoon, they become light pink, and by evening, flowers are a rosy pink.
You can see more about work being done in landscape horticulture by visiting the LSU AgCenter Hammond Research Station website. Also, like us on Facebook. You can find an abundance of landscape information for both home gardeners and industry professionals at both sites.