An evergreen climbing shrub growing wild on tall trees and on rocks; young shoots clad with starry down and in the climbing state adhering by aerial roots. Leaves entire, stout and leathery, elliptic or slightly obovate in the adult state, pointed, tapered to cordate at the base, 2 to 6 in. long and 1 to 3 in. wide, distinctly net-veined, dark green and glabrous; stalk from 1⁄4 to 13⁄4 in. long. Curious small pits often occur in the vein-axils beneath. In the juvenile plants in cultivation the leaves are less than 2 in. long, heart-shaped at the base, and with stalks 1⁄4 in. or less long. Inflorescence terminal and axillary, sometimes a columnar panicle as much as 6 in. long and 31⁄2 in. wide, sometimes smaller and more rounded, but always made up of numerous small corymbs, each of which is enclosed during the bud-stage in four papery bracts, and in that state are globose and 1⁄2 in. or more wide. Normally all the flowers are of the small, fertile type, their most conspicuous feature being the stamens, which are up to 1⁄4 in. long; only very rarely are sterile ray-flowers produced. Seed-capsules vase-shaped, 1⁄8 in. wide, with the styles persisting at the hollowed apex. Bot. Mag., n.s., t. 153.
Native of Chile from Aconcagua to Aysen provinces, and of bordering parts of Argentina, from sea-level to about 5,000 ft. It was first described in 1830 under the invalid name H. scandens, but was probably not cultivated in Britain until H. F. Comber sent home seeds from Chile during his journey in that country and Argentina in 1925-7. It has proved quite hardy on walls sheltered from cold, drying winds. Captain Collingwood Ingram has a plant on the stables cottage at Benenden Grange, Kent, which has reached the top of the chimney and flowers freely. Exhibited by him, the species received an Award of Merit in 1952. It is also hardy at Nymans in Sussex. The flowering shoot figured in the Botanical Magazine was from a plant cultivated at Crarae, Argyll.
As in H. petiolaris the climbing shoots with aerial roots are sterile, flowers being produced only on growths of a bushy nature. In the wild it climbs to a great height; the late Clarence Elliott saw it 50 ft high, and in the southern part of its range in Chile, where the climate is very humid, it is said to attain 100 ft.
Although inferior to H. petiolaris as an ornamental, H. serratifolia is of interest as the only member of the section Cornidia that is hardy in the British climate.
Note: The leaves in this species are normally entire or very slightly denticulate – a character expressed in the name H. integerrima, by which the species has been generally known. In the type of H. serratifolia (Cuming 34 from Chiloe) the leaves are serrate towards the apex, but there seems to be no doubt that only one species is involved. The two species were published (in the genus Cornidia) in the same work and on the same page, but unfortunately, in Hydrangea, the combination H. serratifolia (Hook. & Arn.) Phil, has ten years’ priority over H. integerrima (Hook. & Arn.) Engler, and must be accepted as the correct name of the species, inappropriate though it is.