Emmenopterys henryi – do you know the origin of your plant?

There was great excitement when the 30-year-old specimen of Emmenopterys henryi in Cambridge University Botanic Garden flowered for the first time in September 2012. To the best of my knowledge, this is only the fifth flowering in the UK, with two previous flowerings at Wakehurst Place including the first in 1987, and also two at Borde Hill. The specimen at Glasnevin in Ireland has also reputedly flowered. This unusual Chinese tree was introduced into cultivation by Ernest Wilson in 1907. It is occasionally found in collections and is noticeable for the orange-tinged leaves as they emerge in spring. Wilson described it as ‘one of the most strikingly beautiful trees of the Chinese forests’, bearing white flowers about 2 cm across in large panicles and unusual white bracts formed from an enlarged calyx lobe.

Like so many rare flowering events, this one in Cambridge caught the imagination of the media and brought many enquiries and comments, including one from Charlie Erskine, previously Head of the Arboretum at the Royal Botanic Gardens, Kew. As he suspected, our tree was recorded as coming from the Royal Botanic Gardens, Kew, but we held no other information. In the early 1980s, an ailing tree at Kew was micropropagated and surplus material was distributed, and this was the source of our tree. The key fact not recorded in Cambridge was that these propagules came from one of the original Wilson introductions planted at Kew in 1913. Checking the archives at Kew confirmed the origin of our tree and that Emmenopterys was offered on the 1981, 1982 and 1983 surplus lists. It’s likely that many other gardens will have received this material and may be unaware of its origin. The area from which Wilson collected Emmenopterys has since suffered much deforestation and the species is threatened, so this cultivated material could represent important genetic stock.

I am currently writing up Emmenopterys and the Cambridge flowering and would be interested to hear from gardens that received other surplus plants from Kew in the early 1980s from this Wilson collection, for inclusion in the article. I would also be interested to know whether Emmenopterys specimens in other gardens have flowered, particularly those from the original Wilson introduction.

Dr Tim Upson
Deputy Director & Curator, Cambridge University Botanic Garden