Blue false indigo
This beautiful plant is an often used garden perennial and was named the 2010 perennial plant of the year. Its common name refers to one use of the plant. The Cherokees used the plant to create a blue dye, similar to the dye from the true indigo plant (Indigofera tinctoria). Its dried pea-like pods have been used for rattles for children and are popular in dried plant arrangements.
If you break or crush the leaf or stem of a blue false indigo plant, the sap that emerges will turn blue when exposed to air. Also, the dried seed pods of Blue false indigo are used in dried flower arrangements.