Deinanthe is a small genus, of only two species, closely related to hydrangeas and rarely grown in U.K. gardens. Commonly known as false Hydrangeas, the botanical name comes from the Greek Deinos meaning extraordinary, and anthos meaning flower. They are herbaceous perennials, very hardy, slowly forming a clump about 15-18″, 40-50cm tall and wide. They are woodland plants and need partial to full shade and a humus rich soil. Summer moisture is essential – they will not tolerate drying out. Watering should be reduced as the growing season comes to an end.
Deinanthe bifida is a Japanese endemic, introduced to the West by the Russian botanist C. J. Maximowicz in 1860. The flowers are white. A few varieties are available, such as ‘Pink Shi’ and ‘Pink-Kii’, which have pink buds opening to slightly pink-tinged flowers, and may occasionally produce a few sterile florets. It is slightly larger and easier to grow than Deinanthe caerulea. The hydrangea-like leaves are split at the end rather attractively.
Deinanthe caerulea is a Chinese species, native to Hubei, introduced by E.H. Wilson in about 1911. Smaller and slower-growing than D. bifida, it is even less tolerant of summer drought. The flowers are a remarkable waxy purplish blue. It is sometimes sold under the trade name ‘Blue Wonder’. There is also a hybrid between the two species, sometimes known incorrectly as D. caerulea European Form, which has pale blue flowers.
Propagation is by seed, when produced, or more reliably by division in spring.
Japonica Plants Nursery 