Wild Indigo and Blue False Indigo
Wild Indigo (Baptisia australis), a member of the Fabaceae (Bean Family), is a herbaceous perennial that grows to 5 feet tall and blooms in the spring and summer with blue/purple flowers. These plants have historically been used for dye (indigo), hence the name.
More information about this plant can be on this blog post.
Wild Indigo grows primarily in open woods and requires sun or part shade. It is native to the midwest and eastern North America and is rare in a lot of eastern states.
The genus name from the Greek word for dye and species name means southern (Missouri Botanical Garden).