2. Don't forget plants for the caterpillars. Check and see if your state has a butterfly club or check out the NABA website at www.naba.org. You should be able to find a listing for larval plant host species. I always plant plenty of parsley for the swallowtail caterpillars and Asclepias sp. for monarchs. Be prepared for ragged looking plants. By the end of the season my parsley is down to nubs and the Asclepias is often bare stems. If you like a tidy garden don't plant for butterflies.
3. Over the next two or three months butterfly populations will peak so now is the time to check out your local garden centers or arboretums. Don't buy anything (except maybe that spectacular lily, I can keep it alive in a pot until planting time, I'm sure). This is the worst time of the year to establish plants in most of the country. Instead look for plants that are attracting pollinators. Now you may not see many butterflies so instead look for bees. If bees like it chances are good that butterflies will, too. Make a list and plant to buy at least three of each in the fall. Large swaths of color will be more attractive to butterflies than one of each.