When planting, incorporate compost to improve drainage and fertility, spacing plants 30-45cm (12-18in) apart and watering thoroughly. Apply a layer of organic mulch to retain moisture.
Cut back the stalks after the flowers have faded, and tidy up old dead leaves in March. Apply a generous 5-7cm (2-3in) mulch of well-rotted garden compost or manure around the base of the plant in spring. Avoid moving the plant since it resents disturbance.
Where necessary, lift and divide congested clumps in early spring. This plant is quick to establish so spread may need to be checked annually.