PlantAdvice.co.uk

Slender spikes of brilliant yellow flowers on dramatic black stems zoom above large handsome boldly toothed leaves in July and August. This towering deciduous perennial makes a striking specimen plant for a moist sunny border or bog garden. Or try it beside water and make sure it has protection from the strong midday sun.

• Garden care: Protect the young shoots from slug damage using beer traps or environmentally-friendly slug pellets. The plant must be kept moist; line the plant hole with plastic making a couple of holes in the plastic for drainage. Water regularly during periods of drought. Lift and divide large clumps in spring or after flowering. Apply a generous 5-7cm mulch of well-rotted manure or garden compost in spring.