Regarding Florida Betony - It is a mint relative, it does have pretty little flowers, the little white tubers are edible (the native Indians ate them and I used them on salads), it is hardy and invades everywhere. I brought some in my yard in Newberry, FL along with the border grass given to me by a friend and actually sieved my garden soils, trying to get them out of my flower beds with no luck. The plants that I brought from home there when we moved to the far north section of the Florida panhandle - Quincy, FL - were so carefully cleaned when I left there. I sure didn't want to bring it with me. I was afraid - very afraid.
If you are brave enough to try this plant, make sure that it is severely isolated. You might find a natural restaurant which could use those tubers. We just couldn't eat enough to keep them under control.
By the way, it has a nickname and isn't called Rattlesnake weed for nothing, those tubers do look like rattles.
