Kudzu (Pueraria lobata) is commonly dubbed "the vine that ate the South." It is a semiwoody climbing perennial vine botanically related to the pea family. It's known for rampant growth, with vines able to grow up to a foot per day under favorable conditions. Kudzu is an ecological threat because it smothers other plants, girdles trees and uproots poles, trees and shrubs through sheer weight. Once established, kudzu is extremely difficult but not impossible to eradicate.
Appearance
Kudzu vines have deep-green alternating compound leaves with three trilobed leaflets each up to 4 inches across. The entire compound leaf is about the size of a dinner plate. In late summer, kudzu produces clusters of half-inch purple flowers with a strong, pleasant grapelike fragrance. The flowers produce flat, brown, hairy seed pods each containing three to 10 seeds. In the fall, kudzu sheds it leaves.
Growth Habit
Kudzu thrives throughout the Southeastern United States, wherever there's abundant water and sunshine and mild winters. It does best where summer temperatures exceed 80 degrees Fahrenheit and rainfall exceeds 40 inches per year. But kudzu can tolerate a wide range of conditions and soil types. Hard Northern winters will kill kudzu vines but not the roots, so the plant grows back next year. Kudzu grows from an extensive root system centered on a huge taproot up to 12 feet long and 7 inches in diameter, weighing more than 400 lbs. Each taproot system can support 30 or more trailing vines, with each vine reaching up to 100 feet. Kudzu spreads mainly by underground rhizomes and surface runners. It also can propagate from seeds.
Killing Kudzu
Kudzu's massive root system must be removed or killed in place or the vine will keep coming back. If you can't uproot the root system, you can eventually exhaust the taproot's carbohydrate supply by cutting the vines off at ground level and keeping the plant closely mowed down. This may require three or more years of vigilant trimming. Cattle will eat kudzu, so grazing is another means of keeping back the vine, but it will take four years of grazing to kill kudzu. Herbicides can kill kudzu, but the most effective ones aren't licensed for homeowner use. Household herbicides effective against kudzu include glyphosate and clopyralid. Spray leaves and the ground around the root. Herbicides may take several years to kill kudzu. Eradication efforts should start as soon as the weed is noticed.
Origins
Kudzu, a native of Asia, was brought to the United States in 1876 for the Philadelphia Centennial Exposition. It was promoted as a forage crop and ornamental plant and was planted on hills and roadsides for erosion control. But by 1953, the U.S. Department of Agriculture recognized kudzu's dark side and removed it from the list of recommended ground covers. In 1972, the USDA officially declared kudzu a weed pest. But by this time, kudzu was well-established.
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