Butterfly bush, Buddleja davidii is invasive and we do not recommend planting it. The plant self seeds and displaces desirable plants. Here is our invasive plant list
However, there are some butterfly bushes that do not seed themselves, are sterile, and can be used as nectar plants but the butterflies will not breed on the plant.
Look at The native plant list on our website http://extension.umd.edu/hgic/earth-friendly/recommended-native-plants-maryland Many of the wildflowers such as butterfly weed attract pollinators and butterflies but you will have to match the plants to your site sun/shade and consider mature height and width of the plants.
If you want butterflies to breed in your garden you have to choose the appropriate plants with some knowledge of butterflies common to your area, as well as provide caterpillar host and nectar plants. See the attached link for more information on butterflies and gardening http://extension.psu.edu/natural-resources/wildlife/landscaping-for-wildlife/pa-wildlife-8