Aligator weed, Eurasian Water Milfoil and Giant Salvinia are problems in texas for many reasons. The first reason is, they have no natural predators or other preventives to stunt their growth. On top of this they are all prolific reproducers too. Many of them don't have to pollenate to reproduce they can clone themselves, often times just by breaking apart, which often happens when removal is attempted on them. Since they form such high populations, the decaying plant matter often causes decreases in oxygen levels in the water system. They also clog irrigation pipes, impede boat activity and ruin bodies of water for recreational use.

-Ahab