News Release Distributed 07/22/10
By LSU AgCenter Horticulturists Dan Gill, Kyle Huffstickler and Allen Owings
Most people think of mid-summer as the “down time” in the landscape. Many of our warm-season bedding plants from earlier in the spring and summer have a tendency to not be performing as well by the time we get to late summer. And heat does take its toll on many landscape plants. We do, however, have a wonderful assortment of tropical plants that can be grown very successfully in south Louisiana. Bananas and cannas frequently come to mind, but you can find much more to try.
Pride of Barbados is a great small-growing tropical tree. You see more of these planted in Houston, San Antonio and Austin, Texas, than you do in south Louisiana, but we should use these plants much more. Whenever garden centers have them in stock, they sell very quickly. The scientific name of this plant is Caesalpinia.
Pride of Barbados plants usually are 5-8 feet tall by fall and start producing orangish-red flowers on the terminal growth in mid-summer. Stems are spiny, and foliage is fernlike. Because this plant is in the legume family, it sets seed pods similar to those on beans. These generally are perennial in most of south Louisiana, even through our growing conditions and the cold weather this past winter. They will be an annual in north Louisiana.
Homeowners should consider the white and red flower forms of Texas star hibiscus (Hibiscus coccineaus) for south Louisiana landscapes. They are a hardy perennial, unlike the popular tropical hibiscus. Large five-petal flowers appear in early summer and continue through fall.
Texas star hibiscus plants go dormant in the winter and start re-growing from the roots in April. The flowers attract birds, butterflies and bees. This plant is commonly confused with marijuana, so don’t be surprised if the police show up or someone harvests foliage from your plants. The rose mallow-type hibiscus also flowers great through the summer – even more so than the traditional tropical-type hibiscus.
Cassava is a tropical, shrubby perennial that goes by the scientific name Manihot. The variegated form is the one you see used in landscapes. These plants are not abundantly available at garden centers, and when cassava are available, garden centers sell them quickly.
Alternanthera is what we used to call Joseph’s coat. The foliage of most alternantheras is multi-colored. The most spectacular of these is the variety Brazilian Red Hot. This plant may be a perennial in protected landscapes in south Louisiana, but in most years it will probably be best treated as an annual.
Copper plants also continue to be popular. The common copper plant in Louisiana is called Louisiana Red. Of course, this variety is known for red foliage on a vigorously growing plant. Other new copper plants include Bronze, Beyond Paradise, Bourbon Street and Swizzle Scissors. Most of Louisiana provides annual growing conditions for copper plants. In extreme south Louisiana, they could be perennials during mild winters.
All of these are great landscape plants for late summer in Louisiana. Keep in mind, however, that you may need to plant them earlier in the season to get the most spectacular show you can have as we continue into early fall.
Visit LaHouse in Baton Rouge to see sustainable landscape practices in action. The home and landscape resource center is near the intersection of Burbank Drive and Nicholson Drive (Louisiana Highway 30) in Baton Rouge, across the street from the LSU baseball stadium. For more information, go to www.louisianahouse.org and www.lsuagcenter.com/lyn.
Rick Bogren