Mulanje Cedar (Widdringtonia whytei) Project

The Widdringtonia whytei story

The genus Widdringtonia is an African member of the Southern Cypress family Cupressaceae, subfamily Callitroideae. Comprised of 4 species (W. nodiflora, W. schwarzii, W. cedarbergensis and W. whytei, their closest relatives are the Australian Cypress genera Callitris and Actinostrobus. The Mulanje Cedar, Widdringtonia whytei is listed as Critically Endangered and endemic exclusively to the Mount Mulanje massif in southern Malawi, East Africa, where it is the national tree. It grows at high altitudes between 1,500 and 2,550 meters within the Mount Mulanje Forest Reserve, inhabiting rocky, acidic soils in a cool, misty climate and is now believed to be functionally extinct in the wild, so the race is on to save the species from extinction. 

Our association with this species started by chance in 2019 with a visit to the IJG by Dan Luscombe, Collections Manager for Bedgebury National Pinetum and Forest (Kent, UK) during a holiday in Australia. Dan was heavily involved in designing nursery trials to propagate and grow this species as part of a Darwin Initiative Award program through BGCI in collaboration with two Malawi-based Conservation and Forestry Trusts. While the Bedgebury team was able to germinate the seed, the seedlings could not be grown successfully because of the unsuitable climate in the UK. Dan was very interested to see that we were successfully growing two Widdringtonia species (W. schwarzii and W. cedarbergensis) in the IJG and Tonia and Dan hatched a plan to conduct germination trials and grow insurance specimens here at IJG to distribute to other Australian botanic gardens in suitable habitat as a metacollection project using some of stored W. whytei seed from Bedgebury, whose viability was decreasing with increasing storage length.  

Through a grant awarded by BGCI and ArbNet in 2021, we were able to start the long process of importing W. whytei seed into Australia for germination and propagation trials. Because of Australia’s very strict biosecurity measures, we required the appropriate permits and biosecurity clearance, and because of its rarity, W. whytei was not a recognised species on Australia’s plant import register, so we had to start from first principles to register the species with Biosecurity Australia. W. whytei is also listed under the Convention on International Trade in Endangered Species (CITES), which requires international permits for trade under exceptional circumstances. The W. whytei Australian metacollection project was deemed important for the species’ survival, so CITES permits were granted to IJG. The import process was further complicated by Covid restrictions, but we persevered, knowing the germination rate of the stored seed was lessening every year. We were finally able to import 200 seeds in July 2023, after phytosanitary certificates were provided by Bedgebury and using IJG’s Seed Importer’s license issued by Biodiversity Tasmania. The seed was placed in cold storage over the remainder of the Australian winter to give the best possible chance of germination. 

In September 2023, germination trials by our expert propagator Jonathan ‘Jonno’ Esling commenced with 100 of the seeds. Two different germination methods were used: fifty seeds were trialed using the method developed by Bedgebury which involved incubating the seeds and controlling the temperature and light (Jonno repurposed an old refrigerator for this). The other 50 seeds were germinated using a technique Jonno had developed for germinating Callitris seeds. We knew from X-ray examination of seed prior to leaving Bedgebury that approximately 40% of the seed was viable, but despite this, Jonno managed to germinate 43 W. whytei seedlings which grew very quickly. The germination rate from both methods achieved similar results, so the following year the remaining 100 seeds that had remained in cold storage for the additional year were propagated using the “Callitris germination method’ and a further 44 seedlings germinated, bringing the total to 87 seedlings from 200 seeds, a little over the expected maximum germination rate. 

IJG was able to start distributing seedlings to other botanic gardens from April 2024. We have now planted several specimens in the IJG where they are growing well. The following institutions are also part of the Australian W. whytei metacollection project, having been gifted seedlings from IJG: 

• Australian National Botanic Garden Canberra. 

• Royal Botanic Gardens Sydney, NSW. 

• Blue Mountains Botanic Garden Mount Tomah, NSW, 

• Albury Botanic Gardens, NSW. 

• Mayfield Gardens, Oberon NSW. 

• Royal Botanic Gardens Melbourne, Victoria 

• Dandenong Ranges Botanic Garden, Victoria. 

• Geelong Botanic Gardens, Victoria. 

• Mount Lofty Botanic Gardens South Australia. 

• The Tasmanian Arboretum, Tasmania. 

We still have a few seedlings available to distribute, so please contact us if you are a botanic garden in a location that this species may grow and thrive. As a montane species, specimens require cooler conditions and moist well drained soil, although they don’t like frost. We are hopeful that together we can grow the specimens to seed-bearing age and perpetuate the species, eventually sending seed back to Malawi to give their National Tree a second chance. 

Clanwilliam Cedar, Widdringtonia cedarbergensis, which is endemic to the Cedarberg Mountains in the Western Cape Province of South Africa is also listed as Critically Endangered and the IJG has also been successful in growing this species from cuttings and seed and distributing them to most of the above gardens, as this species is also struggling in its natural habitat.  
 
Special thanks go to Jonno for his amazing efforts to germinate seed with limited viability and for testing new germination methods for this species.  

We also thank the following: 

• BGCI and ArbNet for the funding opportunity and Amy Byrne and Sue Paist from the Moreton Arboretum, USA where ArbNet is based. 

• Alex Hudson (Plant Conservation Project manager-Africa and the Indian Ocean Islands at BGCI) for his support of the project and assistance with procuring the CITES permit. 

• Dan from Bedgebury for visiting IJG during his travels in Tasmania in 2019 who instigated this project and trusted us with such important seed material and who visited IJG again after the 7th Global Botanic Garden Congress, Melbourne in 2022. 

• Emma Bacon from Bedgebury kindly helped with the phytosanitary permits and the CITES re-export permit 

• The horticulturalists and managers at the recipient institutions above for their willingness to contribute to the Widdringtonia whytei Australian metacollection project and for their care of the precious seedlings entrusted to them.  

Find out more about the Widdringtonia whytei

Smith, P. (2015): Saving Malawi’s National Tree: BGjournal , Vol. 12, No. 2, pp. 34-36.  Published by: Botanic Gardens Conservation International (BGCI) [to read, right click and select 'Open in new tab']

Bayliss J., Makungwa S., Hecht J., Nangoma D., and Bruessow C.(2007): Saving the Island in the Sky: the plight of the Mount Mulanje cedar Widdringtonia whytei in Malawi. Oryx Vol. 41 (1) pp 64-69.

Mitrani, L.M. (2017): Reproduction and Establishment of Two Endangered African Cedars, Widdringtonia cedarbergensis and Widdringtonia whytei. Masters Thesis