Linda, I had never heard that either. In Florida, I know we have to be careful due to the invasive nature of the plant, but that's the only warning I've ever heard about butterfly bush.
Oddly enough, I found out this year that there is a plant that will fool the Long-Tailed Skipper. It will lay its eggs on Wooly Pipevine (Aristolochia tomentosa) even though it is not a proper host plant for that butterfly; it is a host for the Pipevine Swallowtail and Polydamas Swallowtail which is why I planted it. When I saw Long-Tailed Skipper eggs on it I was thoroughly confused but I read a blog on the internet where a lady had the same thing happen and she consulted a professor (I believe it was at UF) and he confirmed the phenomenon. The leaves of Wooly Pipevine feel very similar to the butterfly pea or even plain green beans that the skipper uses, but I would think it would "taste" different to the butterfly. Apparently, it doesn't because I had eggs all over it. Luckily, I also grow butterfly pea so I have plenty of the "real" host plant for the Long-Tailed Skipper. Just thought I'd share in case anyone else chooses to grow the plant.
