Perennial

D. ferruginea

Striking, honey-coloured flowers, which are attractive to bees, are densely packed around the stiff spires of this elegant perennial. An architectural plant in both summer and winter. 1.8m. AGM. RHS H6, USDA 4a-8b.

D. grandiflora

This clump-forming perennial boasts large, pretty, primrose-yellow flowers with pointed petals. Its soft tones combine well with almost any other colour. Herbaceous so dies back in winter. 60cm. AGM. RHS H6, USDA 4a-8b.