Welcome to the Wildflowers and Pollinators forum Dave
I am sorry I didn't see your post till just now, and I hope you will be a frequent visitor.
Gardening for butterflies is a lot of fun, I have planted and take care of three butterfly gardens, one at home, one at a local museum and one at a wildscape.
I am always amazed when I hear someone say that they have a lot of native milkweeds growing wild near by, because milkweeds have been very difficult for me to grow, all except the Tropical Milkweed, Asclepias curassavica, and although it is not a native plant it does the job. I do have those and probably can send you seed later on.
In the meantime be sure to plant lots of plants native to your area, both for larval food and also nectar.
Here is a list of native plants recommended for Tennessee that will give you a good idea of what is good to plant in your area.
http://wildflower.org/collecti...
Have fun, butterflies are so beautiful and taking care of their needs is a great adventure
Josephine.