Hydrangea arborescens L.

A deciduous shrub of somewhat loose habit 4 to 10 ft high; young shoots rather downy at first, becoming glabrous. Leaves broadly ovate, oval or roundish, 3 to 7 in. long, 2 to 6 in. wide, pointed at the apex, rounded or heart-shaped at the base, coarsely toothed, upper surface bright dark green, lower one paler, both glabrous, or with down only on the veins or in the vein-axils beneath; stalk 1 to 3 in. long. Corymbs flattish, much branched, usually 4 to 6 in. across, with few or no large sterile flowers. Fertile flowers dull white, very small and crowded; flower-stalks downy. Seed-vessels eight-ribbed, with calyx adhering at the top.

Native of the eastern United States, from the State of New York southwards; introduced by Peter Collinson in 1736. A vigorous and hardy species, which flowers freely in July and August, but is not particularly attractive.

From the Supplement (Vol. V)

The H. arborescens complex has been revised anew by R. E. Pilatowski in Castanea, Vol. 47, pp. 84–98 (1982). He rejects the treatment adopted by Elizabeth McClintock in her monograph on the genus and keeps H. cinerea and H. radiata as distinct species, asserting that the three taxa maintain their distinctness even when they overlap in geographical distribution. For the characters of H. cinerea, see H. arborescens subsp. discolor in the main work, page 385, and for H. radiata see H. a. subsp. radiata, page 386.

cv. ‘Grandiflora’. – In the newly introduced ‘Annabelle’ the flower-heads are larger than in ‘Grandiflora’ (up to 1 ft wide on pruned plants), but that does not really make it an improvement. Raised in the USA. A.M. 1978.