Baptisia

The False Indigo plant is native to the USA.
 So called for the old fashioned species Baptisia tinctoria which was used to dye cloth blue. The results were less than indigo but native Americans and settlers made do with what was available.
For an in depth look at this great garden perennial see the link 
http://www.clemson.edu/extension/hgic/plants/landscape/flowers/hgic1184.html

In my garden, on the right 'Screaming Yellow'
In the middle 'Carolina Moonlight'
At the top 'Purple Smoke' beneath the arching branches of Buddleia alternifolia .
The common blue Baptisia australis is not blooming yet. I bought the white version yesterday at Growing Wild Nursery.
The Baptisias set lots of seed if you leave the decorative pods on and I must have a thousand seedlings which are easy to pull or you can just cut off the seed pods before they open. I am hoping for some fabulous color combination from open pollination. Seed pods were called Indian Rattle and they do!