Hydrilla verticilata is the scientific name for this noxious
invader from afar. No-one knows for sure where hydrilla is
native to, yet its believed that it probably originated
somewhere in southeast asia. This assumption comes from the fact
that its main biocontrol comes from Pakistan. Willows in the
genus Salix have the tendency to take over floodplanes and
wetland areas. There is debate where or not they were introduced
but there is no doubt that they can grow very weedy. In areas
like the overflow of the Mississippi, like where we are in this
episode, its often the only tree growing and thus forms large
monocultures.