|'Hiraethlyn' is a tree-like, deciduous, spreading shrub, 12 feet high by 15 feet wide, with whorled branches. Leaves are obovate, dull green, toothed, to 2 1/2 inches long, and held in clusters on the terminal ends of shoots. Creamy, bell-shaped May flowers, with dark red veins are held in pendent, corymb-like racemes in groups of 5 to 15. Leaves turn yellow to orange in the fall. Excellent grown in a woodland setting.