Verbena officinalis
Ancient medicinal herb with tonic and restorative properties, held in high esteem since classical antiquity.  Used in the traditional European medicine internally (as tea or liqueur) for treatment of infections and fever.  Small airy pale lilac flowers which attract bees and butterflies. Easy to grow, tolerates poor soil and drought. Full sun.   Perennial which self seeds freely on waste ground. Height to 50cm. 9cm pot. Certified organic plant.