Purple (H10) flowers, VII–VIII; dark green foliage; slender, upright habit; height 31–45cm; spread 31–45cm.
Wild-collected; found at Colligan Bridge, Mourne Mountains, Northern Ireland, by Brian O. Mulligan (then Assistant to the Director, RHS Gardens, Wisley; latterly Director, University of Washington Arboretum, USA) in August 1936; introduced by the Royal Horticultural Society’s Gardens, Wisley, Surrey, England, in 1957.
Named after the locality in County Down where it was found.
