This year when planning what to plant, I consulted my state's website with information on which butterflies are native to my area, and they included the info on which plants are nectar sources and which are host plants. I live in Washington State, and here's the page:
http://wdfw.wa.gov/living/butt...
For those in other states or countries, here's another resource:
http://www.thebutterflysite.co...
Once you know which butterflies are capable of visiting you, then it's much easier to make a list of which host and nectar plants you need. Without that, it's SO overwhelming. Honestly, I was still pretty overwhelmed even after narrowing it down to natives. Thankfully, there are some common ground plants that will serve many butterflies (both nectar and host) as well as hummingbirds.
