Do a little research on the butterflies and their favorite plants for your area. Your local plant nursery can help you with this and they are easier to contact than a naturalist. You can also try your local botanical garden or simply visit them and take note of the plant names. I suggest that you get perennial plants, since their life cycle is longer than that of annuals. Try including some firebush(Hamelia patens) not only does it attracts butterflies and bees but is excellent for attracting hummingbirds.