1 litre sized pot.  This hardy versatile perennial is a great addition to the garden.  It copes with a variety of growing conditions, dealing with shade and full sun.  It flowers more freely in a sunny position and it gently seeds itself around the garden.  It has tall, elegant spires of purple flowers held above sage-like green foliage.  In cold winters it will die back and re-emerge in spring but in my garden it acts as an evergreen.  Reaches up to 60cm tall and flowers throughout summer.