Global: The Red List of Rhododendrons


Botanic Gardens Conservation International (BGCI) has published a Red List of Rhododendrons report assessing the conservation status of the Rhododendron genus. Research by BGCI and Royal Botanic Garden, Edinburgh shows that a quarter of the 1,157 Rhododendron species are under threat in the wild.

One species (Rhododendron kanehirae) would be extinct but for collections in botanic gardens (one of which is at Edinburgh) and another species is now completely extinct.

close up of rhododendron flowerThe 128 page Red List of Rhododendrons report designates Rhododendron plant species according to a classification system for conservation status from the International Union for the Conservation of Nature known as IUCN Red List Categories and Criteria.


Rhododendron kanehirae flowering at RBG, Edinburgh (Logan) in June 2011.


The report shows that of the 1157 Rhododendron species surveyed their conservation status was: Extinct 1, Extinct in the Wild 1, Critically Endangered 36, Endangered 39, Vulnerable 241, Near Threatened 66, Data Deficient 290, Least Concern 483. Consequently, 316 are considered threatened with extinction and therefore require conservation action (i.e. they are classified as Critically Endangered, Endangered or Vulnerable).

Rhododendrons are beloved by horticulturists around the world for their flowers. But as the report notes, they are also valued for their medicinal properties, and in some communities they are used for firewood, timber, teas, honey, wine, jams, narcotics, etc, and also as sources of insecticides. For the environment (‘ecosystem services’), rhododendrons grow in areas of high rainfall and high humidity on acidic soils; conditions under which few plants would survive. They stabilize slopes and protect watersheds, notably in the Himalayas where so many of Asia’s major rivers start; and they support a wealth of biodiversity too.

The internationally adopted Global Strategy for Plant Conservation (for 2020), calls for 75 per cent of all threatened plants to be conserved in ‘ex situ’ collections (e.g. botanic gardens); in the case of Rhododendrons this equates to 238 threatened species. BGCI estimate that 65 per cent of threatened Rhododendron species are currently held in conservation collections. Further research is required, especially in relation to where there is data deficiency.

Sara Oldfield, Secretary General of Botanic Gardens Conservation International, said:

“Rhododendrons are back in fashion as garden plants but in their natural habitats they are in trouble. Horticultural skills are urgently needed to restore endangered Rhododendron species in China and other parts of Asia where they are important components of mountain ecosystems. BGCI is committed to help save these beautiful plants from extinction.”

Copies of the Rhododendron Red List report can be downloaded for free (PDF) 

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