A deciduous shrub up to 8 ft high; with the young wood, leaf-stalks, and flower-stalks, also the under-surface of the leaves, covered with a greyish down or felt. Leaves alternate, ovate, 1 to 2 in. long, toothed, thick and felted beneath in a wild state, thinner and less downy under cultivation here. Flowers of a deep blue, and arranged in dense clusters on the upper part of panicles 3 to 6 in. long, which appear in the leaf-axils towards the end of the current season's growth.
Native of Mexico, whence it was introduced in 1818, and of Guatemala. It is not thoroughly hardy at Kew except against a wall. One of the parents of the numerous race of garden hybrids (see C. × delilianus), its influence is always traceable in the fine blue flowers, the downy leaves, and often the tender constitution of its progeny. The typical plant, which flowers from July until the first frosts of autumn, is now uncommon.