How about some Stinking Nanny?

Ragwort has all sorts of enemies and all kinds of strange sounding names. It also goes by St. James-wort, staggerwort, and stammerwort.

It was once believed to cure horses of staggers and people of stammers; quite a colorful past.

Google ragwort and you can find all sorts of ways to destroy it and reasons you should. Apparently it is also a slow acting poison.

Some places have even imported a moth to destroy it. Such prejudice for such a bright and sunny wildflower.