Conserving Rhododendrons

Rhododendron hyacinthosmum, a vireya from Papua New Guinea with a delicious scent reminiscent of, but much nicer than, hyacinths.

 I am recovering from an intensive couple of days in Edinburgh, where I attended a conference on the conservation of Rhododendron species, both in the wild and in cultivation. As curator of the collection in Ray Wood at Castle Howard I am responsible for maintaining alarge number of plants, some of which are very rare indeed: a fellow attendee asked if we still had R. lanatoides, as there were only three known plants in cultivation. Fortunately we do.

Organised by the the Rhododendron Species Conservation Group, with strong support from Botanic Gardens Conservation International and the Royal Botanic Garden Edinburgh, where the conference was held, the talks and discussions ranged widely across the mountains of Asia and the gardens of the world. It was an extraordinary gathering of knowledge, with a collective knowledge of rhododendrons and their localities such as can seldom have been gathered together before. These snippets of conversation give something of the flavour:  'I've seen it on the Doshong La'; 'They're all hybrids up there'; 'the bulldozers were going flat-out, there'll be nothing left now'; 'it's a new species'; 'there are several new species up there'; 'it has hairy pedicels'; 'I don't fancy that road in an earthquake'; 'I don't know why they bother with Sapa, north-eastern Vietnam is much better'; 'you get permission from the Maoists, not the government'; 'we're going into Burma this year.' I've only seen a handful of rhododendrons in the wild, so could only listen, but it was exhilarating stuff.

A tiny vireya from New Guinea, Rhododendron rubineiflorum. The size can be judged from the Oxalis leaf.

We did get the chance to look around the garden on Saturday afternoon, with guided tours led by the official experts Drs David Chamberlain and George Argent. George's speciality is Rhododendron subgenus Vireya, an almost exclusively tropical group, with no hardy representatives. In consequence it is poorly known in this country, but in fact vireyas account for a third of the total diversity of the genus. They are most abundant in Indonesia and on the island of New Guinea, usually growing in the higher, cooler parts of the forest, sometimes being confined to single mountaintops which makes them of particular conservation concern. Their floral shape and coloration is incredibly diverse and their fascination is undeniable, so my pictures today are all of vireyas, but they only graze the surface of their variation..

R. himantodes, an epiphyte from Borneo.

R. loranthiflorum 'Dick Shaw'

Another Papuan species, R. aurigeranum

 

R. taxifolium, collected by George Argent from a mountain in the Philippines where the forest was being cleared for cabbages: it is regarded as Critically Endangered in the wild.



Breeders have been working on vireyas since the 19th C: this is 'Ne Plus Ultra'. Cultivars are very popular in places such as Hawaii and New Zealand.