Achillea or Yarrow are semi-evergreen perennials which are grown for their fern-like aromatic leaves and daisy-like flower heads. These clusters of flowers are borne in summer above the foliage looking like hovering spaceships, lasting for a few months attracting all sorts of beneficial insects to the garden. These insects and creepy crawlies are not just the pretty ones but also the kind that seek out and eat some of the undesirable pests that make them great companions to plant near more troubled plants. They can range in height from 45cm to 100cm, grow well in all soils and particulaly well in dry poor positions with the best results in full sun. The name Achillea comes from the fact that they have all sorts of herbal medical benefits and Achilles used to carry it with him into battle to treat bleeding.