VERNONIA ARKANSANA ‘MAMMUTH’
This improved form of the Arkansas ironweed is a tough perennial with stiff, upright stems that are feathered with lance-shaped, grey-green leaves. It blooms in late summer offering clusters of fluffy, rosy-mauve flowers. These develop into fluffy, rust-coloured seedheads - hence its common name ironweed. These elegant stems look good throughout the winter and should be cut down at the beginning of spring. Works well with tall grasses such as Miscanthus sinensis that also keep good structure through winter. AGM*.
Height and spread 2m × lm.
Origin Garden (species east central USA).
Conditions Rich and fertile soil; full sun or partial shade.
Hardiness RHS H7, USDA 5a-8b†.
Season of interest August - October.
Tom Coward is head gardener at Gravetye Manor in West Sussex
