Growing Hibiscus in North Louisiana
Growing Hibiscus in North Louisiana
Helen Webb
8/19/20264 min read
Growing Hibiscus in North Louisiana
By Helen Webb, Sabine Master Gardener
Hibiscus comes in a variety of species, and many of them are wonderful choices for Louisiana landscapes. Because it includes a number of popular ornamentals, the Hibiscus genus is well known among Sabine gardeners. Species of Hibiscus are members of the Malvaceae or mallow family along with such plants as cotton, okra, hollyhock and Turk’s cap.
Many gardeners are familiar with the Hibiscus genus though the tropical or Chinese hibiscus, Hibiscus rosasinensis. Other commonly cultivated Hibiscus species include Althea, Confederate rose, Texas star, and rose mallow or “hardy” hibiscus. All of these plants make outstanding choices for North Louisiana landscapes.
The tropical hibiscus is well known for its glossy, dark green foliage and nonstop flowers in shades and blends of pink, yellow, orange, white, lavender and scarlet. Its blooming season is very long, running from late spring through the first frost.
As the name implies, the tropical hibiscus is native to mild climates and can be damaged and even killed by severe freezes. Still the tropical hibiscus typically is hardy in South Louisiana landscapes and may even survive milder winters in northern Louisiana. To enhance their cold weather endurance, you can apply a thick mulch (about 8 inches deep) around the base of the plant to save the crown, or plastic sheets when temperatures lower than 30 degrees are expected.
If you prefer not to risk a choice variety in the ground, hibiscus plants make outstanding container plants. When winter arrives, you can move your container plant indoors to a sunny window where it will be safe from the cold.
In the ground or in containers, hibiscuses will bloom best in full sun. An even supply of moisture is important, especially in containers that tend to dry out quickly. Fertilize hibiscus plants once at the beginning of the growing season with your favorite slow-release fertilizer. Feel free to prune them occasionally, as needed to control their size, even when they are in bloom. Pruning is almost always needed for these plants when they are grown in the ground. Generally, major pruning is done in early spring.
Other members of the hibiscus family that grow well here are Althea, also known as Rose of Sharon, which can mature to a size of 10 feet by 5 feet, the Confederate rose, which can change colors when it blooms (more about that later), the Texas star and the hardy hibiscus. The Althea is completely hardy throughout Louisiana. It will grow in full sun to part sun in well-drained locations. The Confederate rose can achieve a size of 10 feet tall and 10 feet wide so plant where it has plenty of room. They prefer full sun and are not that picky about drainage.
The foliage of the Confederate rose is killed by winter freezes in Louisiana. They are reliably root hardy throughout the state. Prune it in early spring to remove any cold damage and shape the plant. Three forms of Confederate roses are grown in Louisiana. “Rubra” produces single, light red flowers about 3 inches across all summer. Two double forms bloom from October through December or first freeze. One form opens large (4 to 5 inch) light pink flowers of exquisite beauty that age through the day to a dark pink/light red. The other double form opens its flowers white and through the day turns dark pink/light red. The changing flower color is interesting and gives this hibiscus its species name— “mutabilis”—which means changing. The first time I saw this I was amazed that the flowers on it looked red, white and blue and on the same plant!
The Texas star is an outstanding species, which is native to Texas and produces large (5 inches or so) star-shaped red flowers on tall plants that reach up to 8 feet tall. There is also a white-flowered hibiscus. The star-shaped-dark green foliage is lacy, giving the plant a light, airy personality. Flowers are produced over a long period from May until early fall.
The hardy hibiscus is similar to the Texas star, but it produces much larger flowers—the size of a dinner plate—in a wider range of colors, including white, pink, rose and red, some with contrasting eyes. The foliage typically is heart shaped and an attractive medium to dark green. Depending on the variety planted, the size ranges from about 2 feet tall and 2 feet wide up to about 6 feet tall.
Hibiscus can survive in a fairly wide range of moisture and sunlight conditions, making them useful in a variety of situations. They will produce fewer flowers in low sunlight conditions. They are outstanding when planted at the edges of ponds, where they can reflect the water. Equally at home in typical garden beds or in boggy soils, this plant is great in aquatic gardens, in low or wet areas and in traditional garden beds. They are often planted to provide height at the back of a border or flower bed.
During the summer months, the LSU AgCenter recommends fertilizing hibiscus to keep them growing and blooming vigorously, especially those in pots. A slow-release fertilizer is the easiest, with one application to the plant in the spring. High phosphorus fertilizers are not recommended. In the fall, the plants will decline and go dormant. The dead stems that remain can be pruned back to living tissue and new shoots will emerge in spring each year.