Rhododendron huanum
Another fantastic new rhododendron introduced from my first expedition to China is the species R. huanum which occurs in scattered populations in the mountains of southern Sichuan, northeastern Yunnan, and adjacent northeastern Guizhou. Although this species has long been known to botanists (it was officially described in 1939), it was never successfully introduced into cultivation in the west until 1995 when Peter Cox and I found it growing with an amazing assemblage of plants in the Jin Pin Mountains of South Sichuan. Among the plants observed (in a very quick late afternoon survey) were Berneuxia thibetica, Lonicera crassifolia, Primula moupinensis and the following species of Rhododendron – argyrophyllum, ririei, lutescens, strigillosum, orbiculare, insigne, ochraceum, and asterochnoum (the last two named species were also first collected for introduction at this time). In cultivation, this species forms a well-shaped rounded shrub with attractive smooth green leaves. The new growth and foliage of huanum is particularly attractive as it emerges a glossy olive-green with bright, red-purple perulae and petioles. The lilac or reddish-purple flowers of this species are what really grab your attention however. They appear in mid-April and have the bonus of darker nectar pouches. It is a color not seen in any other species. The poise of the flowers adds to their charm, hanging from their long pedicels to display their large, brightly-colored and fimbriated calyces most effectively.
Plants grown from this collection of seed in 1995 can be observed in the RSBG growing along the main road between the Big-Leaf Garden and the Meconopsis Meadow.
Strangely enough, this species was not collected again until 2012 when I once again found large populations of it on two separate peaks. The first of these was the famous Fan Jing Shan of eastern Guizhou Province. While it was fantastic to see this rare species in the wild again, and in a completely different region, I was perplexed at the late season of flowering (it was early June) and in the coloration of the flowers, they were a pale lavender-pink, quite different in appearance from the plants in Sichuan and blooming almost two months later in the season. A few days later we were in southern Chongqing (east of Sichuan Province) where we found large populations of this same species on the isolated mountain known as Jinfo Shan, home of the rare conifer Cathaya argyrophylla and the endemic Rhododendron platypodum. As on Fan Jing Shan, the plants were in full flower in early summer and almost pink in color. Obviously, these plants growing at the eastern and southern ends of the range of the species had not read the book.