Most readers will be familiar with Kew's public face; its plant collection; its historic buildings and glasshouses as well as modern additions. Some will be familiar with its place in the history of the Empire; sneaking rubber out of Brazil to create the plantations of Malaysia and quinine to keep the Raj functioning. Members of SCI's Horticulture Group were treated to a look behind the scenes to see some of the activities that are less obvious to the average visitor.
Our tour started in the School of Horticulture. Established in 1963 the school provides a diploma course for 14 students each year. They undertake a three-year course spending nine months each year on practical work in the gardens and three months in lectures. Since they are regarded as an essential part of the Kew workforce, they are paid. However, as our guide for the day Martin Staniforth, the School's Practical Training Co-ordinator, pointed out, 'they will not get rich on their wages, but it helps them survive!'
The students' 'practical' time includes regular sessions on plant identification and cultivating a vegetable plot. This was our next port of call, to see the well laid out plots guarded by stout fencing designed to keep out badgers - but ineffective against pigeons.
A brisk walk then took us much of the length of the gardens to see the Stable Yard where Kew's organic waste is converted into compost and mulch. David Barnes, Kew's Manager of Horticultural Support, described how all the plant waste from fallen leaves and grass cuttings to tree trunks is continually bought to the yard. Here it is mixed with water and the stable manure (mostly straw) from the Royal Horse Artillery Stables at St Johns Wood. Further water and turning raises the stack temperature above 60°C which kills all weed seeds and disease spores. This process converts the softer waste into compost while the chipped logs make excellent mulch for top-dressing. Kew has invested £1.8 million in equipment for this operation but saves £0.5 million in land-fill tax each year, not to mention the cost of buying in compost and mulch.
At this point we were joined by Lucy Garrett of Kew's Conventions and Policies Science team (CAPS). CAPS is a section of the Herbarium which monitors all the international conventions relevant to Kew. Lucy described how the unit links Kew with organisations such as CITES (Convention on International Trade in Endangered Species), FAO (United Nations Food and Agriculture Organisation), CBD (Convention on Biological Diversity) etc and ensures that Kew is following the practices laid down in these conventions. CAPS is also about to conduct an audit to assess the impact of climate change on the gardens. Some effects have already been noticed and David Barnes pointed out; 'The mowing season has extended so much that we have difficulty managing to service all the equipment'.
The Stable Yard is next to Kew's new 'Tree Walk,' so we climbed the steel structure to walk among the tops of the trees. The walkway is constructed of 400 tonnes of weathered steel which has been left unpainted so that the rusting pylons blend with the trunks of the trees. This part of the garden was planted by Capability Brown so the trees are mostly native and only two had to be removed during construction. The walkway not only gives fine views of the tree tops, but also provides an aerial view of the magnificent Victorian Temperate House. The Walkway has proved a major attraction pulling visitors to the far end of the garden, where most never ventured.
We then returned close to our starting point, where Professor Monique Simmonds showed us round the Jodrell laboratory. This along with the taxonomic work in the Herbarium is the heart of Kew's science. The two units work together, since a major part of the laboratory's work is providing the scientific backup (from traditional wax sectioning to modern DNA relationship studies) to the taxonomic studies of the Herbarium. While Kew's world famous seed bank at Wakehurst Place in Sussex keeps a seed stock of plant species, the laboratory keeps DNA reference samples for similar reasons.
Back in the 1980s the laboratory concentrated its efforts on the search for new products that could be obtained from plants. This was in some ways a continuation of Kew's role in the days of Empire, when it helped move rubber from its home in Brazil to the plantations of Malaysia, and the cinchona tree from which quinine is extracted to enable Europeans to survive in tropical colonies where malaria was rife. These are just two examples of how Kew helped the developing Empire to have control over the production of raw materials vital to its continued development.
This role ended when the CITES convention gave the rights to such discoveries to the plant species' country of origin. This initially discouraged further searches for novel products from native flora. Much of the laboratory's effort is now directed towards product authentication. This includes such diverse work as the authentication of natural extracts for Boots' Botanics range to assisting police and customs to tell the true identity of imported plant material. Prof Simmonds described how they train customs officers to tell the difference between the roots of poor-man's ginseng (Codonopsis) and the real thing (Panax) and Chinese star anise (Illicium verum) used in Asian cooking and Japanese star anise (Illicium anisatum) which is very similar but highly toxic, as well as many other species either imported as cheap substitutes or adulterants.
One interesting case they were involved with was that of the young child victim of ritual killing whose torso was found in the Thames. Painstaking studies of the child's stomach contents identified the plant species used to drug him, and from that they were able to localise where he came from.
The laboratory has also helped a South African village in the 'Garden Route' to propagate their own plants for herbal medicines which they could no longer collect from the wild because the land had been developed for game parks. In yet another lab they were using wood sections to identify products made from illegally-felled endangered species. Here the problem can be quite complicated as illustrated by a wooden blind in which several timbers had been used including illegally felled Ramin (Gonostylus). This type of work has resulted in a collection of some reference 100,000 slides which the team is currently trying to digitise.
In the basement area the lab holds a reference collection of some 800,000 species of fungi, soon to be joined by the Commonwealth Mycological Institute collection to create the largest fungal reference collection in the world.
Our final visit was to the Tropical Nursery. This area is used to propagate and maintain the plants used in the public display glasshouses, eg flowering orchids to decorate the Princess of Wales Conservatory. However, its more scientific work revolves around developing propagation techniques for endangered species so that they can be bulked up in readiness for reintroduction to their wild habitat. Christopher Ryan, Manager of the Tropical Nursery, here showed us the St Helena Redwood (Trochetiopsis erythroxylon), a species now extinct in the wild and even in collections severely dwarfed by inbreeding depression. Kew is cross-breeding and selecting for more vigorous plants to overcome this. A few plants of Nescodon mauritianus survive hanging on steep cliff sides in Mauritius where it has been out-competed by tropical weeds. Kew, in collaboration with France's Conservatoire Botanique National de Brest, is propagating this species to return to its native island habitat. Another species is Ramosmania rodriguesii from the nearby island of Rodrigues. This heterophyllous plant has strap-shaped juvenile leaves that are less attractive to the native tortoises than the broader leaves that develop beyond their reach. More importantly it has uses for the treatment of venereal disease.
Although only scraping the surface of this historic institution, the group left with a good picture of the important place Kew retains in both scientific knowledge and exploration for the UK and the world.
by Peter Grimbly
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