Interview with Dr Chris Thorogood, Head of Science & Public Engagement, The University of Oxford Botanic Garden & Arboretum

Note -All images on this page credit - Dr Chris Thorogood, except the Fennel image which is public domain.

15th December 2017.

1. Thanks for answering some questions, firstly can you tell us a bit about yourself? What made you interested in plants, what is your education and current job?

I have been fascinated by plants for a long as I can remember. I spent my childhood growing bizarre and unusual things such as carnivorous and parasitic plants. I have carried this passion with me ever since and I’ve been fortunate enough to see some incredible plants in their natural habitats. I loved science at school, so studying biology, and botany in particular, was a must for me. In 2005 I won a scholarship to carry out my PhD research on parasitic plants. This was great because it gave me the freedom to explore the biology of a group of plants I have had a lifelong passion for. I chose to investigate how parasitic plants called broomrapes (Orobanche spp.) form new species due to their preferences for particular host plants (the plants they extract food from), using molecular, DNA-based techniques in the lab. I am currently the Head of Science and Public Engagement at the University of Oxford Botanic Garden and Arboretum. You can find out more about the research I do on evolutionary genetics in plants here:

2. Can you tell us a bit about the Oxford Botanic Garden and Harcourt Arboretum, what are the botanical highlights and are they open to the public?

I am very fortunate to work where I do. Oxford Botanic Garden in the centre of Oxford, and its sister site, Harcourt Arboretum a few miles away, are the jewels in the crown of the University of Oxford. Together they house one of the most diverse plant collections (for their size) in the world, with over 4,000 species and many more cultivars. Highlights include the unusually diverse hardy euphorbia and carnivorous plant collections at the Garden, and the rhododendrons at the Arboretum. Both the Garden and Arboretum are open to the public, so have a look at the website to see what’s on:

3. You have written a Field Guide to the wild flowers of the western Mediterranean, can you tell us a bit about plants from this part of the world. If someone was going on holiday to the Med and are interested in plants, where would you recommend as the best place to visit? Lavender is the best known British garden plant that is native to the Mediterranean region, do you have any suggestions for anyone looking to plant a less common Mediterranean plant in their garden that can survive our climate?

I’m never happier than when I’m romping around the Mediterranean in the spring! Many people only visit the Mediterranean in the hot, dry summer months but in March and April the hillsides are just ablaze with a riot of yellows purples and oranges as the spring flowers burst into bloom after the winter rains. Anywhere in the Mediterranean is worth visiting in spring but I have a particular fondness for the Algarve (which is on the Atlantic but has a Mediterranean climate), where I taught field botany to undergraduates for many years. Mediterranean islands such as Crete, Sicily and Mallorca are all very rich in endemics (species found nowhere else), and are well worth visiting too. Finally southeast Spain, for example the Cabo de Gata, is a great place to go for a walking holiday in the cooler months of March and April, as this area is home to many plants with North African affinities which cannot be found elsewhere in Europe.

An unusual Mediterranean plant that I think is well worth growing is the giant fennel (Ferula communis), which seems to be quite at home in our climate. Unlike its edible cousin, this monster produces towering, tree-like stems of yellow flowers which are very dramatic. They require patience though: I grew mine from seed and they took seven years to flower – they’re worth the wait though!

4. As an expert in carnivorous plants, what makes them so unique and what is their conservation status? What is your research regarding these type of plants about? Many people are familiar with Venus fly traps, are there any other types of houseplants that are carnivorous, and what would you recommend?

Carnivorous plants have intrigued people for centuries, including Charles Darwin. Incredibly, these ‘killer plants’ have evolved a range of leafy snares to trap, kill and digest animal prey. In fact they’re not unique – they have evolved several times in the Plant Kingdom, always in response to nutrient-poor conditions where animal prey is a source of valuable source of nitrogen and phosphorous. My research examines how pitcher plants evolved, and how they form new species. It’s surprising how little scientists know about the evolution of these extraordinary plants.

Conservation status varies with the species among carnivorous plants. The round-leaved sundew (Drosera rotundifolia), for example, is fairly common in waterlogged environments throughout much of the world. Meanwhile its distant relative, the Portuguese sundew (Drosophyllum lusitanicum), has suffered a huge reduction in its native western Mediterranean over the years, at the hands of plant enthusiasts. It’s now very difficult to find in the wild.

Venus flytraps are familiar house plants. Trumpet pitchers (Sarracenia spp.) also make good house plants. Both can do well on sunny, south-facing windowsills which are kept cool in winter. They like to be kept very wet in summer, so it’s best to keep them standing in a tray of rain water (they don’t like tap water!). Tropical pitcher plants (Nepenthes spp.) are a little fussier because they like relatively constant temperatures and a very high humidity – conditions which can be hard to create in the UK. Some of the commercially available hybrids are easy enough to grow in an aquarium on a sunny windowsill; unlike the previous examples, they don’t like to stand in water, but do benefit from frequent spraying.

5. What has been your best plant exploration adventure so far, and what made it so special?

Borneo! The island has a fascinating flora. Mount Kinabalu in particular is a botanical wonderland, one of the most important mountains, floristically speaking, on the planet. Cloud forests there are festooned in epiphytic orchids and pitcher plants; the higher slopes have a unique alpine flora; meanwhile, the foothills are home to rafflesia, the largest flower on earth, measuring up to an incredible 1.5 m across! Rafflesia is a parasitic plant, hence it has no green leaves or true roots. It has never been grown in a botanic garden outside of its native rainforest before; I recently made a life-like botanical replica which was displayed here at Oxford Botanic Garden in October (Image at the top of the interview). You can hear me explain more about this vegetable vampire here:

6. As well as being a botanist, you are also a talented (and prodigious!) botanical artist. Can you tell us a bit about your work, are you self-taught, or have you had some training, have you had any exhibitions, do you sell prints etc.? Pardon the pun, but do you have any good tips or advice for budding botanical artists?

I’ve painted for as long as I can remember. By the time I was sixteen, my bedroom carpet was a veritable Jackson Pollock canvas (my poor parents!). My father and grandfather both painted too, so painting seems to run in my family. I love to paint in oils because they give a depth and feel that I don’t think other media can easily convey. I use watercolours and gouache, and pen and ink too, for depicting subjects which require a high level of detail. I do not have any prints for sale currently, although I plan to in the coming year. My advice to budding botanical artists would be to get stuck in! The more you do, the easier it gets. And I personally find that painting and illustration are very good for the soul.

7. If someone has a garden in Britain (or similar temperate climate) which they do not do much with, but would like to plant a perennial, tree or shrub that is endangered in its native habitat, but low maintenance, what plant would you recommend and why?

I would focus on what grows well in the garden you have. If you’re lucky enough to have a sunny garden, a bog garden can be an unusual, attractive and ecologically friendly feature. Bog gardens can be adjoined to a small pond, and are a great place to experiment with some of the hardier carnivorous plants outdoors, for example cobra lilies (Darlingtonia californica) and pitcher plants (Sarracenia purpurea). They look stunning growing among other aquatic marginal plants and reeds. By contrast, Mediterranean gardens are often low maintenance in hot dry areas, particularly in the southeast of England where rainfall can be scarce in the summer months. It’s amazing what you can get away with in a well-drained, south-facing border, even in a harsh winter. To recreate a Mediterranean-inspired planting scheme with a difference, I would first go for grasses (Stipa gigantea), shrubs such as cistus, lavender and rosemary, for structure, and then throw in some of the more unusual species such as the giant fennel (Ferula communis: see above), and a dragon arum (Dracunculus vulgaris) or two. Be warned: dragon arums look dramatic but they are pollinated by flies and they smell horrific!

8. This might be a tough choice, but do you have a favourite plant, if so, which plant and why?

My favourite plant tends to change weekly! At the moment it is Cistanche salsa. Poorly known to science, this beautiful parasitic plant grows in the deserts around Israel and Jordan and isn’t yet in cultivation.

9. Is there a specific plant growing in the wild, or a botanically rich place you would like to visit in the future, that you have not been to yet, and if so where and why?

There are many remote parts of the Philippines that I would like to visit. New species are discovered regularly there, including Nepenthes pitcher plants, many of which are threatened with habitat destruction; it’s vital that scientists and conservationists understand what’s there, in order to conserve plants effectively.

Thanks for the answers!

Dr Chris Thorogood

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