Pretty purple flowers make a showy display in late spring, and plants can be grown in containers or in the ground, from the driest sites to poorly draining boggy areas. An African native, both the leaves and flowers can be used in salads and other dishes. Crushed leaves may help cure sinus headaches. The strong odor discourages moles and insects from garden hijinx. The smell repels fleas, ticks and mosquitoes when crushed on the skin — also friends, relatives and neighbors.