Curiosities: What makes a plant or animal ‘invasive’ instead of just ‘non-native’?

Non-native plants and animals are those that come from somewhere else, usually another country. When they start to reproduce in a new location theyâ??re said to be “naturalized.” Only a few of the naturalized plants and animals will become invasive, said Don Waller, a professor of botany and conservation at UW-Madison.