In the past decade here in the Adirondacks several plant and aquatic species have been labeled "invasive species." Efforts have been made to eradicate or at least control, if possible, the spread of these species that in their own growth choke out our native plants.
I'll only show one of them here,.... purple loosestrife. It spreads along roadsides, and into fields. It eventually chokes out the cattails.
Here you can see a few loosestrife plants just beginning to invade a growth of cattails.
A pretty plant, with its tall spikes of brilliant rosy-purple blooms, some people have innocently transplanted it into their home's flower gardens. Over time those people may regret introducing it into their property.
If you wish to learn more about purple loosestrife and other "invaders" you may visit this site: