Invasive garlic mustard hurts native species—but its harmfulness wanes over time

But it may not be necessary to eradicate it to save forests. “In many ways its presence is more of a symptom of a disease rather than the cause,” says Richard Lankau, a researcher at University of Wisconsin. “Things like disturbance, overabundance of white-tailed deer, exotic earthworms—those things often seem to set the stage for bad garlic mustard invasions.”