Hydrangea longifolia Hayata

Still little known in Western gardens, this Taiwanese close relative of Japanese H. involucrata is distinguished by its narrower, lanceolate leaves, the presence of 2-branched hairs among the simple hairs shared by H. involucrata, and its potentially evergreen habit. It was recognized as a distinct species by Hayata (1908). Like H. involucrata its inflorescences open from extraordinary globose ‘drumstick’ buds enclosed in large, deciduous bracts; elsewhere in the genus this is seen only in the climbers of Section Cornidia.

It is grown in Europe from the Crûg Farm collections BSWJ 6883 (E Taiwan 1999), CWJ 12413 (E Taiwan 2007) and BSWJ 14562. Stock at Crûg Farm, North Wales, is given greenhouse protection, Bleddyn Wynn-Jones describing it as a large shrub in the wild, medium-sized and semi-evergreen when cultivated in mild areas (Crûg Farm Plants 2023). A plant in a sheltered corner of Maurice Foster’s Kent, UK, woodland has survived a few years, flowering very late in the year. The species thrives and flowers well in autumn at Tregrehan, Cornwall, a mild and sheltered garden near the coast (Foster 2023; J. Aldridge pers. comm. 2024). However, nurserymen Fabrice Gautier in Brittany, France, though rather further inland also describes it as autumn flowering, but claims hardiness to –15°C (Sous Un Arbre Perché 2024); perhaps this is from another, high altitude, introduction? In warmer parts of New Zealand it is fully evergreen and flowers throughout the year (Woodleigh Nursery 2024).

In North America, a group of three plants reached about 1 m height in Dan Hinkley’s Windcliff garden in coastal Washington State; all were killed outright by the winter of 2010–11, with a minimum of –10°C (Hinkley 2011).