Purple loosestrife kills by suffocation.The roots choke out the native plants,native animals can't find food because of it.There are 2 kinds of beetles in Europe and Asia that weaken it. If these beetles start to eat it, it will take 3-4 years to crumple up and die. It can produce 2 million seeds a year. It is grows by wet places. Purple loosestrife even grows on salt water coasts.