CHAMPAIGN, Ill. - To all Illinois residents: Be on the lookout for kudzu. This high-climbing, fast-growing weed, which is illegal to buy, grow and plant in Illinois, smothers existing vegetation and has been spotted in more than 30 Illinois counties.
"Many people are not aware that kudzu has been found in Illinois," said George Czapar, an extension educator at the Springfield Extension Center of the University of Illinois. In collaboration with the Illinois Department of Natural Resources, Czapar is monitoring kudzu in Illinois and is part of an effort to slow the spread of the creeping vine.
"We try to make people aware of what it looks like, and help document infestations of kudzu" he said. "We hope to make people more vigilant to keep kudzu from spreading."
Kudzu (Pueraria montana var. lobata) is sometimes confused with wild grape, another climbing vine that is widespread in Illinois. Although several species of wild grapes are commonly found in Illinois, they do not spread as aggressively, Czapar said. Kudzu is distinguished from wild grape by its trifoliate leaves, like on soybeans; whereas wild grapes have single leaves alternately attached to the stem.
Kudzu can grow a foot a day, and a single crown may send 30 vines in different directions, Czapar said. Vines can extend 98 feet, and mature vines can be four inches thick, according to the Southeast Exotic Pest Plant Council.
Kudzu was introduced from China and Japan, coming to the United States during the 1876 Centennial Exposition in Philadelphia as part of a Japanese garden exhibit.
In the 1930s, kudzu was touted for its ability to stabilize eroding land and as a food source for cows, Czapar said. The U.S. government promoted what it called the "wonderplant," leading to 2.47 million acres of kudzu-covered U.S. land by 1946, according to the U.S. Department of Agriculture.
Now the invasive vine, a relative of soybeans, covers an estimated 7 million acres across southeastern states. In Illinois, kudzu is located mainly along roads.
"It blocks the sunlight and smothers native plants," Czapar said. No natural enemies or predators of kudzu are common in Illinois, which is typical of an introduced, invasive species, he said.
Southeast Illinois has 90 percent of the Illinois kudzu and the greatest kudzu problem compared with the rest of the state, said Jody Shimp, regional administrator at the Illinois Department of Natural Resources.
The northernmost reported patch of kudzu in Illinois is in Evanston, where there is about an acre of kudzu near the Chicago Transit Authority railroad, Shimp said.
Kudzu has not been identified in Champaign County, but it has been found in Clark, Cumberland, Macon, Peoria, Shelby and Tazewell counties. In 2003, surveys showed that about 100 different locations of kudzu covered 410 acres of Illinois, Shimp said. Most Illinois populations of kudzu cover less than a couple of acres.
Illinois researchers have found that kudzu survives Illinois winters and has excellent germination - characteristics previously assumed to be untrue, Czapar said.
Since kudzu is a host for soybean rust, interest in the weed has increased lately, Czapar said. Soybean rust can cause significant soybean yield loss. First discovered in the United States in November 2004, the rust is now in Alabama, Florida, Georgia, Mississippi and South Carolina, according to the USDA.
The U.I. Extension Center and the Illinois Department of Natural Resources are working together to manage kudzu in Illinois. The Illinois Department of Natural Resources uses both herbicides and mowing to destroy patches of kudzu, Shimp said.
"Because its root system can descend 12 feet into the soil and weigh 300 pounds, controlling kudzu requires a combination of management practices rather than simply pulling out the weed," Czapar said.