Dr John David

John leads the Botany, Herbarium and Registration teams, as well as research projects on cultivated plant diversity, petaloid monocot taxonomy and cultivated plant nomenclature

What do you do?

My role is a diverse one, covering core areas such as cultivated plant taxonomy and nomenclature, but also extending into cultivated plant conservation and the biodiversity and legal aspects relating to conservation, such as invasive alien species. Other areas of interest include plant hardiness linked to climate and aspects of climate change and the impact on the UK’s garden flora.
In heading up the Horticultural Taxonomy team, I oversee all aspects of cultivated plant naming, most significantly in the RHS Plant Finder, but also in the Society’s publications, the names in the RHS Gardens and in RHS Trials. The RHS is International Cultivar Registration Authority for nine different groups of plants from orchids to conifers, an important role in stabilising the naming of cultivated plants. The team also supports the RHS Horticultural Monographs, five of which have been published to date.

The team carries out identification of plants from members and this can link to the research we carry out in plant naming. It also depends upon our Herbarium, which supports plant identification, trials and registration, in holding unique reference specimens that fix the identity of the plant. Our aim is to build a comprehensive collection of specimens of the ornamental plants in cultivation in the UK.

“The UK has an amazing diversity of garden plants and I am committed to researching and documenting them, as well as sharing the information about them.”

Why is your team’s research important?

A name is the key to all the knowledge about that plant, and so accuracy of the name is critical to ensure the link to the correct information.

Projects I’m working on now

  • Narcissus monograph project
  • Systematics of the Scilla group (Hyacinthinae)
  • A revision of the genus Nerine in cultivation

Completed projects

  • In 2015 I helped produce the 6th Edition of the RHS Colour Chart – the standard reference of 920 colours used by horticulturists worldwide for recording plant colours. I have also worked on the reprint of the Colour Chart published in 2020
  • Responsible for the revision of the RHS hardiness ratings system (2012)
  • Systematics of invasive plants of horticultural importance (Ludwigia, Heracleum, Gunnera)


  • Chairman, International Commission on the Nomenclature of Cultivated Plants
  • Chairman of the RHS Nomenclature & Taxonomy Advisory Group (NATAG)
  • Collections Secretary, Linnean Society of London
  • Member of the RHS Bulb Committee
  • Trustee, Stanley Smith Horticultural Trust (UK)


  • Dennehy Z, Bilsborrow J, Könyves K, David J, Culham C. (2021) Dating daffodils to save species. Daffodil, Snowdrop & Tulip Yearbook 2021: pp17–19
  • Garnett G, Könyves K, Bilsborrow J, David JC, Culham A. (2020) The complete plastome of Hyacinthoides non-scripta (L.) Chouard ex Rothm, (Asparagaceae), Mitochondrial DNA Part B Resources, 5 (1), pp1003–1004
  • Könyves K, David JC, Culham A. (2019) Jumping through the hoops: the challenges of daffodil classification. Botanical Journal of the Linnean Society, 190 (4), pp389–404
  • David JC. (2017) Evolution of the species of Narcissus: a review. The Daffodil Journal, 53 (3), pp4–25
  • Brickell CD, Alexander C, Cubey J, David JC, Hoffman MHA, Leslie AC, Malécot V, Jin X. (2016) International Code of Nomenclature for Cultivated Plants, 9th Edition. Scripta Horticulturae, 18, pp1–190
  • David JC. (2016) Climate and weather. Chapter 14. In: Ingram DS, Vince-Prue D and Gregory P (Eds). Science and the Garden: The scientific basis of horticultural practice, Wiley Blackwell: Chichester & Oxford, UK
  • Maarten JM, Christenhusz MJM, Govaerts R, David JC, Hall T, Borland K, Roberts PS, Tuomisto A, Buerki S, Chase M, Fay MF. (2013) Tiptoe through the tulips – cultural history, molecular phylogenetics and classification of Tulipa (Liliaceae). Botanical Journal of the Linnean Society, 172, pp280–328
  • David JC. (2011) A review of plant hardiness in the UK. The Plantsman, n.s, 10 (4), pp222–231
  • Morris M, David JC, Upson T, Buffin M. (2010) Prioritisation for the conservation of cultivated plants – a new approach. Sibbaldia 8, pp111–24
  • David JC (edited & compiled). (2008) Report of the proceedings of a Hardy Nerine Study Day held at RHS Garden Wisley on 26 October 2007, RHS: Wisley, Woking, Surrey

PhD Students

  • Co-supervisor to Zoe Dennehy studying for a PhD on Climate and speciation in the Mediterranean biome at the University of Reading
  • Co-supervisor to Thomas Jones studying for a PhD on British garden plants: a threat to the natural environment due to climate change? at the University of Reading
  • Co-supervisor to Hannah Hall studying for a PhD on Evolution of the Mediterranean flora – squills, bluebells and grape hyacinths at the University of Reading

Get involved

The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.