Thank you. Is the BT persistent?
There are organic-certified plants in a few markets here -- herb plants mostly. I'll have to get the name of that grower and see what I can find out.
It's beginning to sound like if I want to create a garden that actually supports butterflies, etc., I would need to start all my own plants from seed, or get them from people with similar requirements. In other words, that it is not safe to buy plants at a store, period.
I'm still hoping for a work-around of some kind on this one. I have a neighbor who raised this question with me initially and I am passing on what I find to her also.