Modern-day plant collectors defend biodiversity
by Betsy Anderson
Far from a forgotten fad
Speak of plant hunters and swashbuckling tales of long-lost adventurers come immediately to mind. The very words evoke individuals of exceptional stamina, risking life and limb to stock British gardens with the finest selection of plants in the world. The steely determination of a David Douglas—a man more comfortable with conifers than with people—and incredible ordeals such as those faced by Ernest Wilson possess a powerful hold on our imagination. We picture Frank Kingdon-Ward in full plant-exploring regalia, scaling Himalayan peaks with his prized tea thermos in tow or plunging through vast rhododendron thickets in China’s northwestern Yunnan province, once the exclusive collecting ground of a rather intimidating George Forrest. The territorial Forrest, who has been called the ‘Indiana Jones of the plant world,’ cut an imposing figure in spite of his choice of leg-wear: he was never seen without a pair of his signature knickers!
With such visions as these it is easy to see how the plant hunter has become an historical figure. Veiled in romance and lost to the mists of time, our tradition of plant hunting is often pigeonholed as an offshoot of British exploration and the expansion of the Empire, conveniently filed away as a phenomenon of each great—and long past—era of plant discovery and introduction. When we talk of the plant hunters it often sounds as if that chapter of our history is closed. Nothing could be further from the truth. For while the political, social, and technological circumstances that propelled the heyday of plant collecting are gone, plant hunting itself is still very much alive and has taken on vital new significance.
Despite challenges posed by modern travel restrictions and regulations, plant collectors traverse the globe every day in search of new or rare species and varieties. They are sponsored by governments and by scientific organisations like Kew’s Millennium Seed Bank or the International Conifer Conservation Programme at the Royal Botanic Garden Edinburgh, rather than by wealthy enthusiasts or commercial nurseries. Individual countries now take an active role in protecting their native flora, collaborating with collecting teams to ensure both in-situ and ex-situ species preservation. The focus of late-twentieth- and twenty-first-century plant exploration has clearly shifted to emphasize conservation, education, and the defence of biodiversity, demanding more than ever before that today’s plant hunters share the spirit, tenacity, and passion of their distinguished predecessors.
Roy Lancaster, storyteller for the voiceless
More than anywhere else, this legacy thrives in the Hampshire garden of Roy Lancaster. Arguably the greatest plantsman of our time, Roy has travelled the world in search of the beautiful, the rare, and the overlooked, taking him from China to South Africa to the garden around the corner. His discoveries have inspired myriad books, innumerable articles and countless broadcasts on radio and television: a humbling and prolific testament to his energy, enthusiasm and pure love of plants.
Roy has regaled millions with the fascinating histories of our garden plants, particularly those deserving greater attention, such as Itea ilicifolia and its honey-scented cascade of late summer blossom. This large evergreen shrub is native to Western China and was discovered and introduced by Irish botanist Augustine Henry, first flowering in Britain in 1895. Despite its intoxicating perfume and robust character it remains a relatively rare species in cultivation. However, its fragrant, pale chartreuse tassels swathe the walls of National Trust gardens such as Sissinghurst, Cotehele and Castle Drogo, and a vigorous twenty-five-year-old specimen is trained up the west side of Roy’s house
To stroll through Roy’s third-of-an-acre garden is to take a botanical tour of the world, providing a singular glimpse into the life of a modern-day plant collector. Behind every plant is a story, and this dizzying horticultural array will call forth the very finest tales, ranging from the incredible and the amusing to the gory . . . and the gooey, such as a Prunus tomentosa near his terrace, raised from seed plucked from bear droppings in Kashmir.
We could envisage his forerunners engaging in a similar excavation, but it would be difficult to conceive of them rescuing seeds from a washing machine, for example, which is how Mahonia russellii found its way into Britain and into Roy’s front garden. This delicate mahonia, with rosy new shoots, creamy flowers and prolific black fruits was discovered in Veracruz, Mexico by the late Jim Russell, and its seed was brought to this country in 1984 in his shorts pocket. Curious as to what caused the vivid stains in the aforesaid article of clothing, his wife rediscovered the crushed fruit of this graceful shrub as it was about to join a load of dirty laundry. One wonders how many other ‘household’ plant hunters are equally deserving of recognition!
Luckily, Roy doesn’t have to leave home to admire a stunning, nearly black Persian ivy that cushions a passageway between his front and back garden. He discovered Hedera colchica ‘Batumi’ growing wild in the woods outside the Batumi Botanic Garden, on the eastern end of the Black Sea in present-day Georgia. With leaves nearly the size of a salad plate, Hedera colchica is native to the Caucusus and arrived in Britain in the mid-nineteenth century. Travelling through the region in the late 1970s, Roy found several new forms of H. colchica with unlobed or shallowly lobed leaves, like those belonging to the deep glossy ‘Batumi.’ Though introduced in 1979, this handsome variety has only recently become available in the nursery trade, thanks to the renewed popularity of ivies.
This illustrates the supreme importance both of current plant collecting efforts and of initiatives like the Plant Conservation Programme at Knightshayes Court. Unlike trends in architecture and the decorative arts, the comings and goings of fashion in horticulture and garden design can have a deathly serious impact on biodiversity. We could recreate the shag carpet if it ever seemed like a good idea, but in the plant world a forgotten fad might mean the permanent loss of genetic material.
The Plant Conservation Programme (PCP), which Roy has likened to an ark, was established to prevent such losses and protect all plants, fashionable or not. The iconic plantsman’s presence at a recent visioning day for the project was a highlight for all in attendance, as was his gift of six special plants to the National Trust, including the Batumi ivy.
Thanks to Roy, a small corner of the Trust’s ‘Ark’ is now also home to a nodding Japanese chrysanthemum with edible petals (Chrysanthemum ‘Kakiromoto’); an intriguing aucuba (Aucuba himalaica var. dolchophylla) that merits wider cultivation; and the bewitching tree peony ‘Sandrine.’ [LINK] They’re accompanied by a wild-collected specimen of the China rose, Rosa chinensis var. spontanea, ancestor of many of the thousands of roses we enjoy today, and by the fine bamboo Fargesia denudata, introduced by Roy, propagated by the PCP and now flourishing in the gardens of Ickworth, Greenway and Mount Stewart.
Chris Chadwell - The new era of high-altitude plant hunting
National Trust gardens are also an eager custodian of Himalayan plants collected by explorer Chris Chadwell, though the genteel parks, borders and alpine beds of the British Isles are a far cry from these species’ 14,000-foot homeland. An internationally recognised authority on the flora of the Himalaya, Chris recently completed his twenty-second expedition to the region; he organised his first plant-hunting trip to Kashmir in 1983, which was funded in part by the gardens at Knightshayes Court and their newly established Plant Conservation Programme.
Paper fit for a king: the majestic Himalayan birch
It was during this inaugural foray into Kashmir that Chris first encountered the pearly spires of Betula utilis, or the Himalayan birch. Native throughout the Himalaya and into Western China, this deciduous tree reaches 60 feet and is characterised by its dazzling bark, which exhibits enormous variation within its large geographic range: it can appear ghostly white, flushed with a soft pink that gives its peeling strips the same rosy glow as the inside of a seashell, or alternatively it will take on the warm flashings of new copper. Bark colour ranges from rich reds and browns in the Eastern Himalaya to a pure white form known as Betula utilis var. jacquemontii, named for the French naturalist Victor Jacquemont, who was among the first to explore for plants in Kashmir in the early 1830s.
For a garden setting, Chris advocates planting a selection of diversely coloured specimens, noting that stunning effects can be achieved when Himalayan birches are underplanted with the dwarf rhododendrons that are their companion plants in the wild. B. utilis is one of our finest birches, and it has become a memorable feature of numerous National Trust gardens, from Wimpole Hall to Scotney Castle to Colby Woodland Garden. Young trees from Chris Chadwell’s seed are currently being grown on in the propagation unit for the PCP at Knightshayes and will soon be ready for distribution to gardens throughout Britain, where Trust gardeners will strive to highlight their unique colour and form.
In nature Betula utilis is typically observed growing up extremely steep slopes, threaded through by clear mountain streams and framed by a backdrop of glaciers and snowy peaks. The elegant, filigreed appearance of this endangered species belies the strength required to survive in such an environment, though its stamina is hinted at by the distinctive curve that frequently appears at the base of the trunk: this is caused by the persistent pressure of snow as the tree grows, and young seedlings are even forced to contend with the occasional avalanche.
The Himalayan birch has captivated observers for thousands of years, and its striking ribbons of bark have long inspired both creative and practical applications. The inner bark served as a paper substitute for transcribing ancient Sanskrit texts, and to this day forms of the tree in the Eastern Himalaya are known as Bhujapat, which literally means ‘the King’s paper.’ In addition to providing a surface on which to write, the tree’s bark could also be put to more colourful use: pigment from the deeply tinted variants was frequently extracted to illustrate early versions of the Kama Sutra.
In remote Himalayan villages the bark is still collected, albeit for less exotic purposes: it is suitable for packing material and used in fashioning umbrellas and as an alternative to paper. The bark has valuable medicinal properties as well and is utilised in antiseptic infusions and poultices, in ears to relieve earache, and as an effective treatment for ailments ranging from jaundice to hysteria.
Chris’ field notes usually include this type of information. His approach to plant hunting is distinguished by a marked interest in the people who share the plant’s native habitat and their interaction with the species. He freely acknowledges that the relationships he has built with local communities are vital to successful expeditions, a reminder that such associations—either with individuals, organisations or governments—are at the heart of plant exploration today.
Herbarium specimens—not just a pastime of Victorian ladies!
Collaboration was always necessary when plant collecting, but in the past the contribution of others, particularly members of the local population, was rarely recognized. Likewise, Western collectors would descend into a plant’s native habitat to gather seed and herbarium specimens, sometimes taking everything in sight and usually returning home without leaving a duplicate specimen for the herbarium in the country of origin. As a result, it has been extraordinarily difficult for botanists in these countries to study their own native flora.
Fortunately, many projects are now underway to repatriate much of this information through digital photography and the internet—an example is Kew’s repatriation of herbarium data from northeastern Brazil—and preparing a duplicate herbarium specimen for the host country is now a requisite procedure. Chris stresses that a properly prepared herbarium specimen is fundamental to good collecting practices: accompanied by descriptive field notes, a well dried and preserved sample is still the only way to ensure that botanists are provided the detail necessary to identify a plant. Some things haven’t changed since the days of David Douglas!
Despite developments in modern technology, the herbarium specimen remains the cornerstone of correct plant identification, and correct identification is absolutely essential to plant conservation efforts. Inaccurate identification has proved problematic in recent years and is surprisingly prevalent: Chris’ research indicates that at least half of all plant species originating in the Himalaya and named as species are incorrectly identified. The error is compounded when the plant is in a public garden and is given a label; not only will everyone assume the label is correct, but gardeners may not be aware that they are caring for a particularly rare or threatened form or species, making it all the more likely that the plant might disappear from cultivation.
Correct plant identification can be a matter of life or death for humans as well, particularly when the plant in question is important medicinally. Much of Chris Chadwell’s work has centred on Himalayan plants used in traditional medicine, and he has collaborated with the Royal Government of Bhutan and the Tibetan Medical Institute in Dharamsala, Northern India to explore the feasibility of cultivating endangered medicinal species instead of harvesting them from the wild.
From mountainside to garden and back again
One such plant is Podophyllum hexandrum, or the Himalayan mayapple, an attractive herbaceous perennial with charming pink flowers that open in spring on purplish stalks, just as the great palms of its mottled glossy leaves unfurl. In the Himalaya Podophyllum hexandrum is often called ‘bear’s apple,’ as its bright red plum-sized fruit is a favourite snack for the region’s bears. Humans consume the egg-shaped autumn fruit as well, chiefly to soothe coughs and sore throats.
It is the rhizome of the Podophyllum that is most powerful medicinally, however, as it contains an alkaloid called podophyllin, which combats the spread of cancer by interrupting cell division [LINK to yew]. The American mayapple, Podophyllum peltatum, produces this substance as well, though in lower concentration. P. peltatum has been grown and harvested for many years for its medicinal properties, but scientists have only recently begun to investigate opportunities for cultivating its Himalayan cousin, which is threatened in the wild.
Chris Chadwell has been at the fore of efforts to grow Podophyllum hexandrum as a crop in the Himalaya. Observation of the species in British gardens like those at Knightshayes Court, where it is a highly desirable addition to woodland plantings, has convinced him that it lends itself to cultivation and could be successfully raised in a commercial setting. Many of our prized ornamental species are also of great importance medicinally: Arisaema tortuosum, Mahonia napaulensis and Lilium nanum are good examples.
Information gathered from nearly a century of gardening with these showy Himalayan plants is invaluable to those who are trying to protect their wild populations without compromising the cultural heritage surrounding their use. When Ernest Wilson, George Forrest and Frank Kingdon-Ward returned to Britain and unleashed scores of exciting new plants on the horticultural scene, they could scarcely have imagined the impact their introductions would have on traditional Himalayan medicine and on the future of the plants themselves.
Because of the legendary plant hunters of the past, the plant hunters of today, like Chris Chadwell, may arrive in the Himalaya already in possession of their most precious discovery: the inestimable knowledge that is gained by watching, tending and loving a plant for generations.
Plant Conservation Programme, Knightshayes Court
We’re all in this together—
the alliance to save our plants
The spirit of cooperation that infuses plant exploration today is also at the heart of the National Trust’s plant conservation efforts. The Plant Conservation Programme (PCP) provides a forum for head gardeners countrywide to exchange information as well as material from their most important plants, assuring their continued presence in National Trust gardens. But in addition to propagating and distributing plants within the Trust’s collection, the PCP is also committed to augmenting this gene bank with the introduction of new wild-source and botanically or historically significant individuals.
Partnerships forged with other gardens and conservation initiatives have been absolutely essential in fulfilling this aim, ensuring not only that National Trust gardens remain vibrant horticultural showcases filled with interesting plants, but, more crucially, that these priceless plants have at least one, if not several, permanent homes. Sharing our botanical wealth is the best insurance policy available. Never has this been a more critical concern, as 70 percent of plants assessed by the World Conservation Union are at risk of extinction, a statistic that is all the more alarming when we consider that only 3 percent of the world’s described species have been analysed. Rather than simply a showcase for remarkable plants, the garden has become a safe depository.
The pencil cedar of Painshill Park
National Trust gardeners are already curators for the world’s largest collection of historic plants, but these living links to our past will soon be joined by original specimens from gardens like the celebrated 18th-century landscape of Painshill Park in Surrey, filled in the mid- to late-1700s with glamorous new species from the eastern United States. Painshill’s visionary creator, Charles Hamilton, received seeds and plants from John Bartram, a Quaker naturalist who ran a nursery for native plants on his farm in Pennsylvania. Though many of these introductions have been lost over the last 250 years, a surprising number of Bartram’s original collection endure.
Still, Head Gardener Kath Clark is in a race against time to propagate noteworthy specimens before they succumb to age and the ravages of weather. A pencil cedar (Juniperus virginiana) gathered as seed by Bartram in the mid-1700s was felled by a storm in January 2007; luckily Painshill’s gardeners were able to harvest cuttings from this venerable old plant; these were sent to the PCP at Knightshayes where they rooted the following summer. In a few years the plants will be ready to resume their places in this great landscape garden, and duplicate specimens will make excellent additions to National Trust parks of the same era.
Bedgebury National Pinetum
Relationships established with the Forestry Commission’s tree collections—Westonbirt National Arboretum in Gloucestershire and Kent’s Bedgebury National Pinetum—have also brought an array of botanical treasures into the propagation unit of the Plant Conservation Programme.
Since its founding in1925, Bedgebury has quietly but actively been securing the future of hundreds of conifers by planting its 320 acres of parkland with both unusual and apparently common species. The Pinetum currently cares for over 15,000 specimens, representing 60 percent of the world’s temperate conifers.
Here exceptionally rare trees rub shoulders with old, familiar favourites: at present Bedgebury is growing and researching conifers ranging from the Chinese evergreen Cathaya argyrophylla, endangered in the wild and almost unknown in British gardens, to the whimsical, instantly recognizable monkey puzzle tree, Araucaria araucana. The ubiquitous monkey puzzle might seem an odd target for conservation, but in its native habitat of Chile and Argentina populations of this eccentric conifer have been destroyed by grazing, land clearing and fire. Today more monkey puzzle trees can be found in British gardens than in the wild.
As cautionary tales like that of the monkey puzzle occur with greater frequency, it is little wonder that Bedgebury endeavours to increase the genetic diversity of all temperate conifers in Britain, even those that are widely cultivated and have a seemingly indestructible natural population. The Douglas fir (Pseudotsuga menziesii) is an example of such a species. As John Lanyon, head gardener of Knightshayes Court and curator of the PCP, notes, ‘This is a tree we plant all the time, particularly in National Trust gardens and parks. Just think of the opportunities presented by having wild-source Douglas firs available from Bedgebury. Instead of planting a bog-standard conifer, we could plant something really special and encourage biodiversity at the same time.’
In recent years Bedgebury has supplied the PCP with numerous natural-source conifers, including several Pseudotsuga that were distributed to the vast conifer garden at Cragside [LINK] in Northumberland, where National Trust foresters and gardeners have been grappling with a fungal infection of the mighty trees [LINK to Douglas firs]. ‘Bedgebury is looking after all conifers, not only those that are at risk at the moment,’ adds John, ‘and this far-sighted attitude distinguishes them from many other conservation groups.’
Yet among the more than 2,000 species that call the Pinetum home, over 100 are classified as threatened in the wild. Bedgebury is at the forefront of conifer conservation through its work with the International Conifer Conservation Programme at the Royal Botanic Garden Edinburgh. Together these organisations strive to protect conifers that are threatened in their native habitats, such as the Fitzroya cupressoides [LINK] in Chile and Lebanon’s iconic cedar, Cedrus libani. Plant collecting plays a key role in these conservation efforts: natural-source specimens supplement the gene bank of trees in cultivation in Britain and, even more importantly, preserve material that can hopefully be reintroduced to the wild once the threat to the plant has abated.
Fresh hope for the stinking cedar
This approach has lately been implemented in an attempt to rescue an obscure American conifer from impending extinction. Torreya taxifolia, known by the less-than-alluring nickname ‘stinking cedar,’ is an ancient tree that once existed across the entire northern hemisphere. Retreating glaciers left this 40- to 50-foot (12-15m) evergreen scattered in microhabitats in the Southeastern United States, principally in southwestern Georgia and along the steep slopes fringing the Apalachicola River in northwest Florida.
Discovered in the 1830s and named for New York botanist John Torrey, Torreya taxifolia impressed 19th-century observers with its pungent odour, released when its yew-like, deep green needles are crushed (a possible explanation for the epithet ‘stinking’ cedar). Its prevalence was also recorded: as late as 1914 it was described as a dominant species in a Florida forest of beech, magnolia and pine. But sometime during the first half of the twentieth century, something went terribly wrong with the Torreya. From several well-stocked pockets of woodland, the conifer’s numbers have plummeted to a horrifying 200 individuals, strung across a minute range in northern Florida and southwest Georgia.
Scientists to this day are unable to determine exactly what has caused this dramatic downswing in population: many blame a fungal blight, which killed nearly every adult tree by the early 1960s, and the species’ decline has also been hastened by persistent drought and other introduced soil pathogens. Everyone agrees that unchecked habitat destruction and logging for its valuable, rot-resistant timber would have sealed the fate of this once-characteristic conifer, but for the energies of concerned individuals and organisations interceding on its behalf.
Bedgebury National Pinetum and the Royal Botanic Garden Edinburgh have recently joined what is now an international effort to save the stinking cedar. Cuttings from wild torreyas have been rooted at the Royal Botanic Garden Edinburgh and are currently growing at Bedgebury; these trees will be allowed to mature and set seed. Their distinctive fruit resembles nutmeg, but the seed is covered in a fleshy pulp that emits an astonishingly putrid aroma when ripe—an even more likely explanation, it would seem, for the plant’s common name! Seedlings raised from these ex-situ plantations are vital to the species’ future, as native Florida torreyas rarely reach maturity and almost never produce seed: those torreyas that persist in the wild are root sprouts or shoots springing from stumps of trees that were logged or felled by disease.
Across the Pond, similar conservation initiatives put in place by the Arnold Arboretum and the Atlanta Botanical Garden have met with considerable success. In 2002, in collaboration with the Florida State Park Service, the Atlanta Botanical Garden reintroduced Torreya taxifolia seedlings to forest ravines that had not seen the species in decades. Their survival rates are promising.
Awareness about the plight of Florida’s torreya is growing as well, thanks to groups like the Torreya Guardians [www.torreyaguardians.org], a worldwide, self-organised band of advocates who have harnessed the internet to inform the public about the conifer and coordinate measures for its protection. Projects like these are vital to the continued existence of the stinking cedar, but re-establishing the species will be an uphill battle at best. As David Ruland of the Atlanta Botanical Garden, writes, ‘the Florida torreya is a glacial relic, seemingly stranded in an increasingly hostile niche without any natural means of escape or survival.’
Gardens, then, are one of the very few habitats available to a species so acutely in jeopardy in its native environment. Bedgebury hopes their plantation of Torreya taxifolia will preserve and expand an irreplaceable gene bank that can eventually be drawn upon to bolster wild populations of the tree in the United States. They also intend to increase the number of Florida torreyas in cultivation: in
January 2008 the Pinetum sent a hundred wild-source T. taxifolia seedlings to the National Trust’s Plant Conservation Programme. In a few years the plants will find a happy refuge in some of the finest gardens in the British Isles, adding texture and appeal to the landscape while ensuring that the stinking cedar escapes the fate of the great vanishing glaciers that swept it south.