1 litre sized pot.  Sanguisorba officinalis (Great Burnet) is a hardy herbaceous clump forming perennial.  Medium green pinnate basal leaves emerge in late spring followed by stems topped with oval shaped pompom flowers of a rich burgundy colour, reaching up to 90cm.  Always commented on in my garden .  I leave the flower heads on through winter.  A wonderful plant for naturalistic planting.  It grows from a thick rhizome type root base and copes in moist soil types in full sun to partial shade.