The US dumped $500 million into fighting kudzu, the vine that swallowed the South—only for three unexpected species to do the job for free. For decades, scientists waged chemical and mechanical war as the invasive plant smothered forests and power lines.
Kudzu first arrived in the United States in 1876 at the Centennial Exposition in Philadelphia, where Japan displayed it as a garden ornamental. For the next half century, it grew mainly on southern porches, cultivated for shade and its purple flowers. Farmers largely ignored it, and they had practical reasons. A kudzu field took years to establish, the tangled vines were difficult to cut and bale…