Although we typically think of annuals, perennials, and a few flowering shrubs when it comes to attracting butterflies, a few trees also lure these winged jewels. Our native black locust (Robinia pseudoacacia) is one tree on that list. Look it up in a good horticultural reference book and you'll find caterpillars listed as one of its common "pest problems." Because it would require a veritable horde of caterpillars to do any serious damage to this tough tree, don't let the possibility of a few munched-on leaves prevent you from planting one in your garden. The locust's iron constitution also makes it a good candidate for urban gardeners who want to help butterflies survive in the big city.
I once had a lengthy conversation with an old Southern gardener about a plant he referred to as "drunk bumblebee plant." Because I was not familiar with that common name, the gentleman had to e-mail me a photo of his plant before I realized he was describing showy stonecrop (Sedum spectabile). It all makes perfect sense now. Plant some stonecrop in your garden and watch as bees, butterflies, and a host of buzzing insects appear intoxicated by the showy, broccoli-like florets that open pink and gradually take on a maroon cast. It's like an open bar for thirsty bees and butterflies, and the neon "open" sign is turned on from summer through late fall.