1 litre sized pot.  Centaurea hypoleuca John Coutts is a hardy perennial with a long flowering period from summer through to autumn.  Lavender pink flowers reach up to 50cm high on strong stems and regular dead heading helps prolong the season.  Great as a cut flower.  Likes a sunny position and can handle most soil types but would not appreciate wet feet.  Its long green leaves are deeply divided and forms a slowly spreading clump.