Hi Teresa,
Isn't it exciting and relaxing to see who shows up in your garden? In my experience, the best way to get and KEEP them is to be certain to provide lots of host plants as well as a big assortment of nectar plants to give them variety, that way they come to dine at your house as both caterpillars and adults. We'd prefer a loaded buffet ourselves, right?
Host plants on your property will help to insure that small colonies will make your place a permanent home. If any caterpillar habitat nearby your garden is taken away- for example a field or wooded area is razed for a housing development- then there go all your beautiful butterflies!! Our winged beauties have to start life children first. LOL- If you "own" your caterpillars, you wont need to "rent" your butterflies. Pollinator partnership has a super guide with lists of best suggestions for your area, just plug in your zip code:
http://www.pollinator.org/guid...
Here's some eye candy on my fav plants for nectar and leaves
Monarch cat on Butterfly Milkweed plant
Fritillary cat on wild violets
Black Swallowtail on Rue
And here's is the gorgeous outcome in order: