Ashwagandha

This plant is well known amongst ayurvedic practitioners as an adaptogen herb. It helps in building and maintaining a healthy immune system, as well as regulating the nervous system. The whole plant can be used medicinally, though the root is most commonly used in tinctures and teas, or powdered and stirred into milk for a nourishing and comforting drink. The aromatic roots are typically dug in the fall, or can be left in the ground to overwinter for future digging. Self-sowing annual, can be perennialized. 

Photo from Wikimedia Commons