Description: 'Dusky Challenger' is a clump-forming, rhizomatous perennial to 1m tall with narrow leaves. Well-branched stems bear chocolate-scented, dark purple, ruffled flowers in summer.
Care: Grow in well-drained, fertile, neutral to slightly acid loam in full sun; sun on the rhizome encourages flowering. Propagate by division of rhizomes after flowering, from midsummer to late summer. Cut down old flower stems after flowering, and remove any dying foliage in autumn.