People Profiles

William McNamara: Portrait of a Modern Plant Hunter

March 23, 2012


In 1968, Jane Davenport Jansen, a San Francisco-based, plant- and garden-loving heiress, purchased a summer home on forty-acres northeast of Glen Ellen in the Mayacamas foothills of California’s Wine Country.

Like many landowners in this region, she set her eyes on planting vineyards in the open valley of her property.  Two decades later and retired, with a focus on designing the horticultural grounds around her home, Jansen’s garden designer, Roger Warner, travelled to England looking for plants.  There,  a fortuitous meeting took place:  the designer met Lord Charles Howick, who had inherited Howick Hall in 1982 and would eventually transform it into Howick Hall Arboretum, one of the most important new arboretum of wild-sourced trees in Britain.

He proposed that they  begin plant expeditions together to North America. In 1987, in an effort to establish a botanical garden based solely on wild-collected seeds, representatives from what would soon be called Quarryhill went on their first collecting expedition to Japan with Howick and McNamara. Jansen appointed McNamara Director in 1994 and he became Executive Director in 2007.  The first expedition with Kew was in 1988.  A nursery was established on site the following year and by 1990, plants were ready to be turned out.  The remains of the abandoned quarries, in which water collected during heavy winter rains and through which a stream wound through rough terrain and eventually create streams and ponds, would evolve into one of North America’s finest Asian gardens:  Quarryhill Botanical Gardens.

Now approaching its twenty-fifth anniversary, Quarryhill is home to one of the largest collections of scientifically-documented, wild-sourced Asian plants in North America and Europe, many representing ancestors of horticultural favorites throughout the world.  Since its inception, William McNamara, its plant hunter and executive director, has worked at Quarryhill building a garden that fulfills the garden’s mission in ‘Advancing the Conservation, Study and Cultivation of the Flora of Asia.’

This post describes McNamara’s activities as both plant hunter and administrator of this world-renowned botanical garden, provides an overview of the garden’s history, describes rare plants it cultivates, and examines Quarryhill’s status and impact as a botanical garden.

Plant Hunter and Administrator

McNamara’s work concerns propagating species whose survival is threatened due to habitat loss caused by deforestation, over-consumption of resources, agricultural expansion, and over-population.

This interest in conservation began in high school when he read the writing of influential nineteenth-century American author, naturalist and historian Henry David Thoreau whose books, essays, journals and poetry on natural history and philosophy are credited by historians as having helped create the modern ecology and environmental movement.  Thoreau famously wrote about self-sufficiency within nature in the iconic work, Walden. Thoreau’s writing highly influenced McNamara, who pursued this interest by earning a B.A. in English Literature from the University of California at Berkeley and eventually an M.A. in Conservation Biology at Sonoma State University. He is currently completing a PhD in Sichuan University in China.

McNamara aspired to be a university professor, but instead travelled the world, married, and started a family.  To earn money, he began working at a nursery in California’s Sonoma County where he became more knowledgeable about plants, though, he said, “I quickly learned I was going to starve to death if I didn’t do something else quickly, so I started a landscape contracting business which I did for many, many years.” It was through this landscaping work that he met Jane Davenport Jansen who hired him to install the garden Warner designed for the house in the mid-1980s.  Initially, Warner and Lord Howick explored up and down the eastern seaboard of America with assistance from Kew Gardens.  In 1986, Howick came to the West Coast, Jansen met him and thought, “People give money to the opera but nobody gives anything to plants.”

Jansen decided to uniquely use her money for plants and with Howick’s connections to the United Kingdom, suggested that they approach Kew Gardens.  In 1987, Jansen went to England where they approached John Simmons, curator of the Living Collection, about a field trip to China with Jansen’s financial backing.  This resulted in the 1987 trip to China to which Kew sent the Head of the Arboretum, Charles Erskin, and Head of the Palm House and Temperate House, Hans Fliegner. Since their first expedition in the fall of 1987, there began a series of expeditions to China and Haoabn in partnership with Kew with seed collecting activities every year throughout Asia including Nepal and India.

In going to China, a sense of reciprocity developed:  China hosted  visitors from England and America, and then several Chinese would be hosted in England and America – though not as plant hunters, but as tourists.  He has also collected in North America three to four times with Charlie Howick, in the Pacific Northwest as well as the East Coast.  “I also did an expedition into California’s Sierras about six years ago.  In China we found new species but it is extremely rare here to find new species, but in China we have found a few new things.”

McNamara is not a trained botanist and all his fellow plant hunters on these joint expeditions have been horticulturalists.  “We don’t try to do any taxonomic work on our own.  We will collect all our own species and describe them in terms of where it exactly occurs and what the companion plants are, aspect, elevation and all those things are carefully recorded.’  Dried herbarium specimens are taken and those are deposited at Royal Botanical Gardens Kew, Royal Botanical Garden Edinburgh, the California Academy of Sciences, or the Missouri Botanic Gardens.  The group will take two to three sets of herbarium species, leaving one set in China for burgeoning botanical gardens there. While China doesn’t  have well-established botanical gardens with a long history like Kew, there are several throughout the country, including the new Shanghai ChenShan Botanical Garden. According to McNamara, the Chinese have set aside a great deal of land for nature reserves but most are mere lines drawn on maps.”

“They are declared ‘nature reserves,’ but there is no money left for managing them and nobody knows what is in them.  A lot of these were initially set aside for pandas but most scientists think the panda is going to go extinct because these nature reserves, with plants and animals, are not managed well.  In terms of inventory of animals and plants, they don’t know what is in them.  This is really tragic because in terms of inventory, there are over 130,000 plant species in China while only half of that in America and Canada.  This is why Kew wanted to get back in there because of the long history of Kew in China with plant hunters Wilson and Kingdom Ward.

China is “the third largest country in the world containing a vast expanse of physical features and climatic types, from sea shore to high mountains and plateau, from rain forest to desert, from near arctic to the tropics,” according to Roy Lancaster’s Travels in China: A Plantsman’s Paradise, where there are more than 30,000 species of flowering plants including 7000 species of trees, approximately one-eighth of the world’s total. Most of the plants that are being introduced now have been fully documented by Western, Chinese, or even Japanese botanists and as such, botanic gardens have shifted from an initial effort of finding plants for economic and ornamental use to shifting toward conservation, restoration, and education.

Accordingly, Quarryhill is not searching for plants to introduce into the trade though McNamara clarifies that it doesn’t mean they don’t want them to get into the trade.  As a scientific-institution, its staff is small with an executive director, a director of development, director of horticulture, and an administrative assistant, nursery and education manager, garden supervisor and four gardeners, as well as interns and volunteers.  He publishes articles in journals such as Pacific Horticulture and Curtis’s Botanical Magazine (for which he is an International Advisor), published by Kew.

The Botanical Garden

Quarryhill is located along the Sonoma Highway, an east-west thoroughfare through California’s Wine Country northeast of San Francisco.  A small, modest sign marks the entrance and visitors travel down a gravel driveway, past a large greenhouse and Jansen’s vineyard of cabernet grapes to a car park, modest wood buildings, and shady picnic area.  Self-guided maps and Quarryhill’s many docents provide tours.  It is fortunate to be led by McNamara, who is one of the few people in the world who can look at such a rare landscape and know that it has been cultivated from seeds he collected on particular cliffs or mountainsides in threatened parts of Asia.  ‘That feels bizarre,” he remarks, “Especially when I see thirty to forty-foot trees.” There are many flowering herbaceous plants throughout this wild garden and while the foliage is beginning to emerge in a late spring visit, McNamara points out that by June, the landscape will be filled with colour.

A tour with McNamara begins in one of the few designed places of Quarryhill, up a hill to a pergola where weddings and receptions take place.  Here, he explains, are one of the best features of the garden:  the roses.  There are about two hundreds roses in the world, half are native to China, and with the make-up of the modern rose comes roses native to China beginning more than two hundred years ago when hybrid roses from China came to Europe, becoming parents of roses we see today.  Quarryhill has one of the originals – Rosa odorata var. gigantea – a rambling rose whose growth habit makes it unfit for the average garden.

Rosa odrata var. gigantea from China (Yunnan), Myanmar, Thailand, and Vietnam

McNamara describes that plant hunting is an exercise in extremes:  by day, he hikes across varied landscapes and by night, his task is cleaning hundreds and hundreds of collected seeds.   During his two decades of expeditions, he comes in contact with native populations during his expeditions and has witnessed the degree to which the minority people in China have changed.   In the mid-eighties, women especially would still be in their traditional dress, but McNamara remarked that it is changing fast with many more people wear Western clothes, driving cars, and designing their gardens with a decidedly Western interpretation.

Throughout a tour of the garden, McNamara will stop to provide anecdotes about particular plants – for example, Emmenopterys henryi, introduced by the most prolific of all plant hunters in China, Ernest Henry Wilson, 1907.

“Wilson made the bold statement that this was the most strikingly beautiful tree in all of China.  He was famous in his lifetime as he wrote and lectured widely so when he said something like this, it carried a lot of weight and it was widely planted throughout the British Isles.  It grew just fine but it refused to flower.  It wasn’t until 1987 – when it was seventy-five years old, that it bloomed.  And it only had one flower cluster on one branch and it bloomed at Wakehurst Place, but it has never flowered again. Remarkably, ours flowered at six years of age and created such excitement that Tony Kirkham from Kew came over to photograph it and it was written up in British newspapers.”

“It has really unique flowers.  Its terminal flowers has a cluster and its individual flowers are small and tubular of a creamy-yellow but around the outside are white bracts which are a modified calyx.  It gets a lace-cap hydrangea look, but because it is terminal, if it ever blooms heavily, it will be very, very showy. There is one in North Carolina that I’ve been told about. It took more than twenty years, I’ve been told, to bloom but when it flowers, you cannot see the plant.  It blooms in the summertime, and I think that the spring and summer is too cool in England for it to put on enough wood and flower. Ours flowers every other year, consistently now.   We are a total summer drought and we have cold, wet winters. Where this occurs in the wild, it is in dry winters but a very wet summer.”

Indeed Quarryhill’s trees are, as far as McNamara knows, the first to flower in western North America and may be the youngest ever to flower in cultivation, grown from seeds collected during an expedition to eastern Sichuan Province in 1996, in partnership with the Royal Botanic Gardens, Kew and the Howick Arboretum.   Showing extraordinary vigor and health, both have grown as shrubs, lacking a single leader, and have reached fifteen feet and eight feet in height, respectively. The flower buds, first noticed in late June 2004, began opening in July and continued well into August. Due to agricultural expansion, poor forest regeneration, and logging,  Emmenopterys henryi has a wide distribution in southeast China, but is still endangered.  According to the China Plant Red Data Book, it does not flower until thirty years of age and usually sets seed once every two to four years.  Quarryhill’s unprecedented success with this plant helps to ensure its survival despite having a wet, cool winter and a drought-summer.

Throughout the garden are many of Wilson’s findings, collected when he was dispatched to China by the influential Exeter-based Veitch Nursery.  Over his lifetime, he brought back thousands of herbarium specimens to Britain and introduced more than 2000 new species with more than sixty that bear his name.  McNamara points out that there many lilies in the Quarryhill collection including Lilium leucanthum, which grows four-to-five feet tall, and develops beautiful trumpet-like flowers, as well as the famous Lilium regale, the white, strongly-fragrant, trumpet flower lily native to western Sichuan and introduced to England in 1903 by Wilson.

“I had one of [Wilson’s] books with me describing the villages and though the village names have changed, I was able to figure out the vicinity of the areas he was talking about by having his journals with us.  It only occurs in a few mile stretch of the Ming River canyon and so we were heading up the Ming River, and when we got near to where we thought it would be, we started to put our heads out of the window and we were finally able to see it.  Wilson’s incorrectly packing the lilies in clay is an example of the difference between what he did and what we would do:  we don’t dig up any plants.  Wilson dug up plants, and nursery people do that today, too, but it disturbs the habitat and you can bring in pests.  Wilson dug them all up and they all rotted.  He went back two years later and dug them all up and that is when the avalanche happened and he broke his leg.  And so he had his ‘Lily Limp’ because his leg never set right.”

Wilson also loved Cercidiphyllum japonicumbecause of its great characteristic including heart-shaped leaves which, MacNamara says, “give off the scent of burnt sugar or cotton candy or fresh strawberries when you walk over the crushed leaves in the fall.”   Wilson’s presence is made evident again when a large Magnolia wilsonii is seen, a large, spreading shrub or small tree with drooping white tepals and crimson stamens, and a species threatened by habitat destruction and collection for medicinal use in its native provinces of western Guizhou, Sichuan, and northern Yunnan.  However much the presence of Wilson is felt in this and other botanical gardens, there is a distinct difference between plant hunting during Wilson’s time and plant hunting during McNamara’s time which is decidedly for preservation efforts – to protect rare and endangered species in a threatened, rapidly-changing China.

Magnolia wilsonii

Rare and Endangered Plant Conservation

In 1992, McNamara collected just six seeds from just one Magnolia wilsonii on a mountain. Two seeds went to Kew, two went to Howick Arboretum, and two went to Quarryhill.  Only one plant germinated for each institution.  McNamara returned to the same mountain two years later, and it had all been stripped.  It was another habitat of this rare magnolia being destroyed and he believes that all its habitat in the wild could be destroyed in twenty to thirty years.

Indeed, there are many rare and endangered species in the Living Collection at Quarryhill which is helping to ensure that particular plants do not go extinct.  Preserving these threatened species is at the cornerstone of Quarryhill’s philosophy and includes a range of species:

Acer pentaphyllumrare and critically endangered in the wild with botanists estimating that it will be extinct in ten years).

Magnolia sinica possibly the most threatened plant in the garden and only one of two trees in the United States and fifty world-wide).

Liriodendron chinense rare and endangered.

Lirodendron tulipifera — widespread in the eastern United States and a disjunct species – that is, originally part of the same population before the continents separated millions of years ago.

Davidia involucrataonce widely distributed in China, but its distribution area has shrunk greatly due primarily to exploitation and destruction of forest habitat.

Cephalotaxus fortunei var. alpinaerare in China, and listed as threatened in Vietnam by the World Conservation Monitoring Center, it is endangered by both harvesting for timber and medicinal purposes throughout its range.

Magnolia grandis — a very rare tree endemic to only a few places in Yunnan and adjacent Guangxi Province in southern China, it is one of five magnolias prioritized as urgently in need of conservation action by the Kunming Institute of Botany of the Chinese Academy of Sciences.

Pinus roxburghii –a  pine that comes closer than any other other pine to being deciduous, it displays a needle retention time of one year, the shortest of any pine and is considered near-threatened and in need of conservation. Six mature specimens grow in the Highland section of Quarryhill.

Pterostyrax psilophyllus — endemic to central China, this plant is threatened by habitat loss, and under third-class protection under Chinese law.

Rosa rugosaa plant that has become endangered as a wild plant by picking and uprooting, has naturalized in northeastern American, where it has become a weed, but is widely-planted at Quarryhill.

Work on the rare maple Acer pentaphyllum, found only in western Sichuan Province and almost extinct in the wild, exemplifies Quarryhill’s important role in preserving rare plants of temperate Asia.   Two hundred trees, their delicate leaf structure intermingled with native California oaks, have been planted in a conservation grove (see picture below).

“There are now probably more of them growing here than occur in the wild – its habitat is along rivers – and it is about to disappear altogether because of the construction of dams.”  National Geographic funded McNamara to perform fieldwork on this plant, to document its habitat and where it occurs, and threats to its survival which include its use as fuel and that it is heavily cut by Tibetan subsistence farmers as well as deer and goats who eat the seedlings.  The biggest problem is the damming of rivers as the maple occurs in the river canyons and water is going to rise above almost all of these populations.  “When these trees produce seed, we will send the seeds back to China so that they can replant them near where they grow naturally.”

Acer pentaphyllum nursery at Quarryhill


Without a doubt, the latter half of the nineteenth-century and first half of the twentieth-century was the golden age of plant hunting.  A chief goal of plant explorers was China, a paradise and ‘botanical encyclopedia’ with its rich variety of plants that attracted many of the most famous names in plant collecting – Abbé Farges, Abbé Delavay, Reginald Farrar, George Forrest, Augustine Henry, Frank Kingdon Ward, Frank Ludlow, Joseph Rock and Ernest Henry Wilson.  As the effects of the Cultural Revolution began to recede and its ‘doors’ opened again to the West, it was a different China and, according to Hepper in Plant Hunting for Kew, with environmental destruction and severe limitations on where hunters could go.

Many of the localities visited in the past by plant hunters have since been destroyed.  This destruction continues abated and the future for many areas is in doubt.  We must at least be thankful that so many fine Chinese plants are already well established in our gardens. And we should spare a thought for those earlier plant hunters who often endured great privations as well as many dangers in their search for new introductions to cultivation.

Sparked by a chance meeting and funded by philanthropist Jansen, who was justifiably concerned about the state of the environment in post-Cultural Revolution China, her particular vision to conserve, study, and cultivate these plants has since continued, despite her death in 2000, through the efforts of the staff at Quarryhill which have earned the garden an international reputation as a important scientific collection.  In addition to propagating plants, there are concerns about raising the garden’s presence in the region.  A new interpretive rose garden is under construction.  Not only will it be a designed element where receptions and other local events can take place, but it will be accompanied by a narrative about the historical link of roses to China, and is a way of reaching out to the regional Chinese community.

For his work at Quarryhill, both as plant hunter and executive director, McNamara has been the recipient of several rewards.  In 2010, he received the prestigious Scott Medal and Award, given to individuals or organisations which make an outstanding national contribution to the science and art of gardening, presented by the Scott Arboretum of Swarthmore College.  In 2009, McNamara received the Eloise Payne Luquer Medal from the Garden Club, an award also given for outstanding botanical contributions.

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