Kew's nine star plants are registered to the National Plant Collection scheme
Among its many collections of plants, Kew holds nine particularly special ones registered as National Plant Collections. Richard Wilford finds out what this means and why they’re so important.
When you push open the heavy doors at the southern end of the Palm House at Kew Gardens, a plant almost as old as Kew itself confronts you.
Leaning out of its huge wooden container, the great lumbering trunk is supported by props to prevent it crashing to the ground, yet at its tip is a flourish of bright green, palm-like fronds that belie its age.
This is one of Kew’s star plants, Encephalartos altensteinii, a cycad collected by Francis Masson in South Africa and brought to Kew in 1775. Having made itself at home at Kew for more than two centuries, this venerable plant has recently had a change in its status.
The National Plant Collection scheme is run by the National Council for the Conservation of Plants and Gardens (NCCPG). Its aim is to conserve garden plants that may otherwise be lost to science and horticulture, and collection holders may be individuals or organisations.
Of course, the plants at Kew know no difference. Encephalartos altensteinii has grown here for all these years and will continue to do so for as long as it cares to live.
In fact, Kew is obliged to keep national reference collections under the terms of the National Heritage Act 1983 – as curator Nigel Taylor stresses, the Royal Botanic Gardens, Kew, is the national collection of plants.
So why does Kew need to place certain plants in National Plant Collections, when they’re already safe in the collections of the nation’s botanic garden? To find out, I asked those involved in growing these plants to see if they think it’s important.
Greg Redwood is head of the Great Glasshouses and Training Section at Kew, and the collection holder of four of Kew’s National Plant Collections: Encephalartos, Heliconia, Musa and Amorphophallus. These are all tropical genera, which is one reason Greg chose them, as not many other places in the country have the resources to maintain significant numbers of these plants.
“Few growers can provide the constant warmth and humidity, the vast glasshouse space and the skip-loads of compost needed to grow these plants in the UK,” he explains.
You can see what he means when you visit the Palm House. There, in the central section, is a collection of bananas and plantains, all in the genus Musa, that reach to the roof, with vast leaves blocking out the sun.
In the Princess of Wales Conservatory are more star plants, Kew’s titan arums, Amorphophallus titanum. Massive pots are wheeled out of the Tropical Nursery when the plants are put on display, and every year or so one flowers, drawing in crowds of visitors, fascinated by this giant of the plant kingdom.
However, Kew can grow many different tropical plants, so why single out just a few?
Wesley Shaw, who looks after the Palm House, is busy watering the banana plants when I ask him that very question. “Having certain collections highlighted gives us somewhere to start when trying to explain Kew’s work,” he says, “It leads into talking about all of Kew’s collections.”
Christopher Ryan, a manager in the Tropical Nursery, echoes this view: “Kew is such a huge place, with so many plants, it can be hard for visitors to understand exactly what we grow and why. By pinpointing certain interesting plant groups, the whole place becomes more accessible,” he explains.
So the National Plant Collections are a way of promoting Kew and its work. As Christopher says, “It helps get our message across.”
Marcelo Sellaro, a horticulturist in the Tropical Nursery, explains another aspect of the National Plant Collections scheme. “If people know we have certain specialisations, they know where to come if they need to study particular plants for research.”
Kew’s living collections can be used to supply genetic resources when field work isn’t possible, such as the inflorescences of Amorphophallus, recently collected by a researcher from France.
Wakehurst Place collections
National Plant Collections at Kew are relatively new, but the four collections at Wakehurst Place have been established for nearly 20 years.
In the wooded areas of the garden are the collections of southern beech (Nothofagus) and birches (Betula). In various beds near the Mansion you can find the collections of Skimmia and Hypericum.
Nothofagus trees have been grown at Wakehurst for many years, but the collection suffered in the storm of October 1987. Since then, new introductions from Kew expeditions to South America and Tasmania in the 1990s have added many more plants.
Already reaching several metres in height, these new plants can be seen alongside other Southern Hemisphere trees in Coates’ Wood, at the northern end of the estate.
Not far from Coates’ Wood, and just behind the Millennium Seed Bank, is Bethlehem Wood, home of the birch collection. Here the Birch Trail follows mown paths through the vivid green bracken, taking you past birches from North America, Europe and Asia. They include Betula utilis, the Himalayan birch, which can have silvery-white or chocolate-brown bark, and the wonderful Chinese B. albosinensis, with peeling sheets of cinnamon-coloured bark.
Chris Clennett, gardens manager at Wakehurst, showed me the Hypericum and Skimmia collections. His view is that building up a comprehensive collection of a particular genus helps safeguard some of the less well known or less popular forms.
“The range of hypericums seen in planting schemes is generally quite small,” he explains, “with cultivars like ‘Hidcote’ dominating.”
Keeping an extensive collection allows access to more unusual species for research. Chris tells me that the University of London’s School of Pharmacy has been sampling a range of hypericums at Wakehurst on the basis that St John’s wort (Hypericum perforatum) has medicinal properties, so other members of the genus might have too.
“One plant that their researchers sampled has been found to contain an antibacterial compound that may one day prove useful,” he explains.
Holding National Plant Collections involves more than just keeping the ‘star plants’ of a genus. Although these bring in the crowds and help advertise what Kew does, the real importance lies in maintaining a collection that includes the less fashionable and less striking species and cultivars.
You never know what future uses these plants may have.
There is another National Collection at Kew that I’ve yet to mention – the Iris subgenus Scorpiris, otherwise known as the Juno irises, of which I am the collection holder.
So I suppose I should be asking myself the question I’ve been putting to the others at Kew. I must admit, it’s not an easy one to answer, but I think that as a conservation organisation Kew should support the aims of the NCCPG by having these collections.
There’s a lot for visitors to do at Kew, from the thrill of a walk among the treetops to the fun of venturing underground into a giant badger sett.
But it’s vital we also remind visitors what Kew is all about. Collections feed Kew’s science, education and conservation work, and holding National Plant Collections highlights that fact. And without our collections, we can’t fulfil our mission.
Author: Richard Wilford