Chaste Tree aka Vitex (Purple)Latin name Vitex agnus castus Chaste Tree, also known as Vitex, is an attractive shrub or small tree. Its berries, chasteberries, are used medicinally to treat endocrine issues and more commonly hormonal and fertility issues in women. It has pretty purple flowers that are loved by pollinators. It is called chaste berry because it was thought to lower mens libido in the Middle Ages. Plant in full sun and very well drained soil.