Johnsongrass was introduced into the United States early in the nineteenth century; it later became such a damaging agricultural invader that several states declared it a noxious weed

Many invasive plants were originally introduced by people because they were believed to offer practical benefits. One such example is Johnsongrass, which was brought to the United States during the nineteenth century as a forage crop for livestock.

Raccontata datimesofindia.indiatimes.com