| Graham Dugald Duncan | |
| Birth Date: | 1959 11, df=y |
| Citizenship: | South African |
| Fields: | Botany and horticulture |
| Workplaces: | SANBI, Kirstenbosch |
| Alma Mater: | University of KwaZulu-Natal |
| Known For: | South African geophytes |
| Awards: | Herbert Medal Recht Malan Prize |
Graham Dugald Duncan (born 28 November 1959) is a South African botanist and specialist bulb horticulturalist at the Kirstenbosch National Botanical Garden, Cape Town, South Africa.
Graham Duncan was born in 1959 and grew up in the Western Cape region amongst its wild bulbous plants. He obtained his early education at the Cape Town Technikon with a National Diploma in horticulture, and joined the Kirstenbosch National Botanical Garden, Cape Town, South Africa in 1978, where he came under the influence of Winsome Fanny Barker (1907–1994), then curator of the Compton Herbarium at Kirstenbosch and a Lachenalia specialist. He earned his MSc (cum laude) in Botany at the University of KwaZulu-Natal, Pietermaritzburg in 2005.
Graham Duncan is a specialist horticulturalist for geophytes and curates the indigenous South African geophytes collection at Kirstenbosch Botanical Garden. These are displayed in the Kay Bergh Bulb House at the Kirstenbosch Conservatory. He is considered an authority on the cultivation, conservation, propagation and biology of bulbs of the Cape region, and the leading expert on the genus Lachenalia. His research deals with the biology and taxonomy of Cape bulbs.
Other than his work on Lachenalia he is known for his expertise on Nerine, Eucomis and Agapanthus. As well as identifying a number of South African plants, he has also bred cultivars such as Clivia miniata 'Kirstenbosch Splendour', which illustrates the cover of the Kirstenbosch centenary book (2013).
He is the author of numerous books, including several titles in the Kirstenbosch Gardening Series, scientific papers and popular articles on South African bulbous plants. He is also a plant collector and plant photographer (see image) and his photographs illustrate his own books and have been published in The Smallest Kingdom: Plants and Plant Collectors at the Cape of Good Hope (2011).
In 1989, he was awarded the Recht Malan Prize for non-fiction (1989) from the Nasionale Boekhandel for his Bulbous plants of southern Africa and in 2001 he was the recipient of the International Bulb Society's Herbert Medal.
Plants for which Duncan is the Botanical authority include many species of Lachenalia, together with . The International Plant Names Index lists 54 taxa named by him, predominantly species of Lachenalia.
. Duncan. Graham. Graham Duncan (botanist). The Lachenalia handbook: a guide to the genus, with introductory notes on history, identification and cultivation, with descriptions of the species and colour illustrations . Annals of Kirstenbosch Botanic Gardens, vol. 17. 1988. National Botanic Gardens of South Africa. Kirstenbosch, South Africa.. 9780620119535.
. Duncan. Graham. Graham Duncan (botanist). The genus Lachenalia. Botanical Magazine Monographs. 2012. Royal Botanic Gardens, Kew. Richmond, Surrey. 9781842463826.
. Duncan. Graham. Graham Duncan (botanist). Grow Nerines: a guide to the species, cultivation and propagation of the genus Nerine. 2002. National Botanical Institute, Kirstenbosch. Claremont, South Africa. 9781919684338. 24 November 2016. 25 November 2016. https://web.archive.org/web/20161125045227/http://www.alpinegardensociety.net/sales/books/bulbous/Grow+Nerines/313/. dead.
. Duncan. Graham. Graham Duncan (botanist). Grow Clivias: a guide to the species, selected hybrids, cultivation and propagation of the genus Clivia. 2008. South African National Biodiversity Institute, Kirstenbosch. Claremont, South Africa. 978-1-919684-51-2. 2nd.
. Duncan. Graham. Graham Duncan (botanist). Grow Agapanthus: a guide to the species, cultivation and propagation of the genus Agapanthus. 1998. National Botanical Institute, Kirstenbosch. Claremont, South Africa. 978-1919684147. .
. Duncan. Graham. Graham Duncan (botanist). Grow Bulbs: a guide to the species, cultivation and propagation of South African bulbs. 2010. 2000. National Botanical Institute, Kirstenbosch. Cape Town. 978-1919684260. 2nd.
. Royal Horticultural Society. RHS A-Z encyclopedia of garden plants. 2008. Dorling Kindersley. United Kingdom. 978-1405332965. 1136.
. Duncan. Graham. Graham Duncan (botanist). Cultivation and propagation of Freesia species. 96–103. 2011., in
