The following is adapted from several Department of Transportation sources, primarily Roadside Use of Native Plants, a handbook published by the Federal Highway Administration. Beware of invasive species. No, we are not talking about aliens from outer space. Invasive species are plants and animals that are introduced into new areas in which they are not among the native flora and fauna, and because they no longer face the natural enemies or competition from their place of origin, they spread or reproduce prolifically.
Invasive species can be a very, very big problem.
Non-native species can cause significant changes to ecosystems, upset the ecological balance, and cause economic harm to our nation's agricultural and recreational sectors. For example, introduced plants, such as kudzu in the southeastern states and purple loosestrife throughout the country, have choked out native plant species and consequently have altered wildlife and fish habitat. Zebra mussels introduced into the Great Lakes in the ballast water of cargo ships have colonized water pipes, boat hulls, and other surfaces, wreaking havoc on water systems, transportation, and native shellfish. Purple loosestrife and reed canary grass are invasive plants that compromise wetland mitigation projects. Species that are likely to harm the environment, human health, or the economy are of particular concern.