The Vine that Ate the South

Kudzu looks innocent enough, yet the invasive plant easily overtakes trees, landscapes, telephone poles, whatever is in its path. Kudzu grows out of control quickly, spreading through runners (stems that root at the tip when in contact with moist soil), rhizomes and by vines that root at the nodes to form new plants. Once established, kudzu grows at a rate of one foot per day with mature vines reaching as long as 100 feet. Kudzu was brought to North America in the late 1800s as an ornamental and farmers were encouraged to plant it to anchor steep banks of soil and thereby prevent erosion. Sometimes referred to as “the vine that ate the South,” the plant has become a rampant invasive species in parts of the southeastern United States and readily spreads over trees and shrubs, often killing them. Northern winters tend to kill the plant’s stems but allow the roots to survive. Control methods include herbicide sprays, manual cutting and mowing, and the use of goats and sheep. Climate change puts a lot of stress on native species. Invasive species like kudzu are often more adaptable to change than many native plants and can outcompete them early in the growing season. Kudzu can weather dry periods with its deep root systems and then take over where native plants could not survive. Agricultural Research Service (ARS) scientists in Stoneville, Mississippi, reviewed different programs known to successfully suppress kudzu. Mark A. Weaver, a plant pathologist in the ARS Biological Control of Pests Research Unit, and his team used a combination of these programs, including a herbicide-free "organic" system, to achieve a high rate of kudzu suppression and eradication. Weaver states, “What we didn't know back then is that this native Asian plant doesn't control erosion; instead, it hides erosion while quickly gobbling up surrounding landscapes. Kudzu damages or kills other plants by smothering them under layers of leaves.” Typically, it takes about 10 years of persistent herbicide applications to eradicate kudzu. Weaver developed a series of effective management programs that can substantially reduce kudzu over one and two-year periods. Once landowners remove kudzu, they can use their land productively, according to Weaver. They can establish forestry, wildlife habitats and recreational parks. Weaver applied four different herbicides (aminocyclopyrachlor, aminopyralid, fluroxypyr, metsulfuron methy)l and combinations of these herbicides achieved 99 to 100% reduction in aboveground kudzu biomass. A bioherbicide treatment (Myrothecium verrucaria) at three different kudzu-infested sites. A bioherbicide is a biologically based control agent for weeds. He repeated these treatments for two years. Results showed a high level of suppression on the small plots after just one year. An even higher percentage of kudzu—99 to 100 percent—was killed during the second year. The organic treatment, which also established native vegetation, killed 91 percent of kudzu after one year and 95 percent after two years. The treatment involves applying a bioherbicide application, mowing and revegetation. Credits: USDA/ARS