The bold spikes of white flowers with contrasting purple bracts are at their best in mid summer, displayed to advantage above large well-divided dark green leaves.
Sprays of bright orange/red flowers with a distinct yellow centre appear in summer, over grey foliage. A favourite ingredient of many a RHS Hampton Court show garden, it produces masses of flowers ..
ACHILLEA ptarmica 'Boule de Neige' (The Pearl Group)
This variety of Achillea has a button-like flower shape with double white flowers in mid summer, which contrast well with the dark green finely cut foliage.
A tall elegant plant with pale blue flowers in summer. It is excellent for the back of the border as a substitute for Delphiniums, as it is disliked by slugs.