Daniel Gill, Merrill, Thomas A. | 6/30/2006 2:13:19 AM
By Dan Gill
LSU AgCenter Horticulturist
If you regularly read national gardening magazines and get a variety of gardening catalogs, you may have noticed tropical-look landscaping is a trend gaining attention across the country these days.
For Louisiana gardeners this hot concept is old hat. We’ve been gardening in the tropical style as long as anyone can remember.
Of course, there almost always is room to try something new or one more plant, and there are lots of great tropicals you can purchase and plant in your garden now.
In addition to their amazing heat tolerance and outstanding summer performance, we grow tropical plants for a variety of reasons.
Some, such as hibiscus, ixora, canna, angel trumpet, bird-of-paradise and butterfly ginger, are grown for their beautiful, and often fragrant, flowers. Others, such as peacock ginger, caladium, elephant ears and copper leaf plant, are grown for their attractive, colorful foliage.
The best tropicals are those that reliably survive winters where you garden. Despite their tropical origins, many are hardy throughout the state if given some winter protection.
Gardeners who are working with shady areas will find a gold mine of shade-tolerant plants among the gingers. In their natural habitats, most gingers grow under the canopies of trees in filtered light – although some grow in the open at the edge of water and in sunnier conditions. Generally, gingers will do best where they receive direct sun for about two to four hours a day and should not be planted in hot, sunny, dry locations. Shell ginger and some types of Curcuma and Costus will, however, grow in full sun.
There are many different gingers that can fill a variety of gardening needs. Low-growing gingers, like peacock ginger and smaller species of Curcuma or Globba, make great ground covers or clumps at the front of shady borders. Medium-sized gingers, which grow 3 feet to 6 feet tall, include species and cultivars of Curcuma, Hedychium and Costus, while the shell ginger grows 10 feet to 12 feet tall. These larger gingers are excellent choices for accent, screens or at the back of a border.
Of course, no other summer-flowering shrub surpasses the tropical hibiscus (Hibiscus rosa-sinensis) for glossy, dark green foliage and nonstop flowers in shades and blends of pink, yellow, orange, white, lavender or scarlet. The long blooming season runs from late spring through November or later.
The tropical hibiscus thrives in sunny locations and looks great in beds or containers. It is one of the more tender tropicals and will not reliably survive temperatures below the mid-20s. Still, they are readily available and not too expensive, so it’s easy enough to replace any lost to winter freezes. Better yet, if you grow them in containers, you can move them inside on cold winter nights.
There are a number of species of Clerodendrum that we grow for their beautiful, fragrant flowers and, in some cases, ornamental fruit. They may freeze back during especially cold winters but reliably return from their roots.
Perhaps the most well known is the cashmere bouquet (Clerodendrum bungei). Effortlessly easy to grow in part shade to shade, cashmere bouquet produces 4 foot to 5 foot tall stalks with large clusters of small, fragrant, mauve flowers. Just remember that it spreads rapidly.
Many of the clerodendrums produce stems that run underground and produce plants some distance from the original plant, but none are quite as bad as cashmere bouquet. If you are aware of this habit and promptly remove sprouts from areas where you don’t want them, this is not a problem. But if you are the type of gardener who is not inclined to keep a careful eye out and remove them as necessary, you probably shouldn’t plant those that spread rapidly.
Other great clerodendrums include harlequin glory bower (Clerodendrum trichotomum). This large shrub to small tree looks as tropical as the rest, but it is quite hardy. It drops its leaves in the winter but does not freeze back. In June or July, large clusters of very fragrant white flowers come on and last until August. Then amazing turquoise fruit continue the display. But it also spreads rapidly.
Another clerodendrum that produces attractive fruit after its long, tubular, white flowers is C. indicum. Although not common, I’ve seen this tall (up to 12 feet) clerodendrum growing in southern, central and northern Louisiana. And it actually spreads slowly.
As a group, clerodendrums are very attractive to butterflies and hummingbirds. One is even called butterfly shrub (Clerodendrum ugandense) because of the exquisite blue, butterfly-shaped flowers it produces. And this is one that does not spread.
Including tropicals in the landscape has many rewards, but you do need to be aware of how hardy the plants you choose are and be prepared to protect them when and if necessary.
Many gardeners find it well worth the effort, however, and I think you will, too – particularly when you seen them perform like troopers and produce beautiful flowers and foliage through the hottest part of the summer.
Get It Growing is a weekly feature on home lawn and garden topics prepared by experts in the LSU AgCenter. For more information on such topics, contact your parish LSU AgCenter Extension office or visit our Web site at www.lsuagcenter.com. A wide range of publications and a variety of other resources are available.