An invasive species is a non-native organism whose introduction to an area causes, or is likely to cause, damage to ecosystems. Many species of invasive plants, most introduced deliberately, have become established in the South. Certain invasive species, like kudzu, are now so widespread that they have become iconic symbols of the South.
With its long growing season, relatively high rainfall, and warm climate, the South is hospitable to many invasive plants. Kudzu, Japanese honeysuckle, and wisteria are among the invasive vines introduced to the United States from Asia for ornamental purposes. Kudzu, “the vine that ate the South,” was introduced to provide attractive ground cover and control rampant soil erosion caused by poor farming and forestry practices. Kudzu grows at a prodigious rate and can climb over trees, smothering all vegetation below its thick canopy of foliage. Like most invasive plants, it is very difficult and expensive to remove once established.
Chinese tallow, mimosa, princess tree, and tree-of-heaven are some of the South’s major invasive tree species. All were deliberately introduced to the United States for their aesthetic beauty and, in the case of tree-of-heaven, ability to grow in extremely poor soil. This hardiness is often desirable in garden settings and urban plantings, but it makes these trees very difficult to eradicate from forests. They tend to displace and shade out native species, blocking sunlight from reaching the forest floor and preventing the growth of native plants.
The South also hosts many species of invasive grasses, which include giant reed and cogongrass. Cogongrass, which can grow to six feet tall, is an extremely aggressive invader, forming dense colonies that exclude all other vegetation. It has minimal food value for wildlife, and its rapid establishment in an area can greatly reduce the amount of edible plant material available.
Some species, such as Chinese tallow, are capable of invading intact forests. Most invasive species, however, prefer disturbed sites and edge habitats. Roadsides, agricultural field edges, and recently harvested timberlands are often prime locations for invasive plants to gain a foothold in the landscape. People and equipment can unwittingly spread the seeds of invasive species on their clothes or in tire treads.
For more information on invasive plants in the South, visit the University of Georgia’s Center for Invasive Species and Ecosystem Health