Longwood Graduate Fellows present findings on threatened plants to tree care

Longed Graduate Fellows present findings on threatened plants to tree careMillions of people visit public gardens each year. As they linger in the luscious landscapes, stress levels power down and new information may take root — on chemical-free pest control, perhaps, or the ID of that perfect perennial to jazz up a faded flower bed, or the role public gardens are playing in saving plants headed for extinction.

Botanic gardens and the people who love them have a major ally in the master’s degree program in public horticulture offered by the University of Delaware in partnership with Longwood Gardens.

The program, the oldest of only three offered in the U.S., produces leaders of botanic gardens around the world. As part of their academic training, which is fully funded by the program, each Longwood Fellow explores a research topic important to keeping these green spaces growing.

“Their research has to be applicable to our industry — we need it,” says Brian Trader, interim director of the graduate program. Trader is based at Longwood Gardens, in Kennett Square, Pennsylvania. Its four-acre conservatory and over 1,000 acres of outdoor gardens attract more than a million visitors annually.

The cohort of six Longwood Fellows graduating this spring presented their research to the public on May 29 in the Longwood auditorium.

Sarah Helm Wallace used Todsen’s pennyroyal, a rare mint plant that grows on the mountain slopes of New Mexico, as a springboard into her discussion of “exceptional, threatened species” — plants that are dwindling in number and produce only a few seeds or no seeds at all.

Although not much is known about the role of Todsen’s pennyroyal in the ecosystem, researchers do know the ecosystem in which it lives is complex, supporting bighorn sheep to hummingbirds, Wallace pointed out.

“It isn’t ideal to lose a species,” she said. “Shouldn’t we try our hardest to keep it around?”

Protecting endangered plants increasingly requires strategies for growing them in plant conservatories and using tissue culture and cryopreservation techniques to be able to store and propagate them later on, Wallace said. As part of a world plant diversity safety net, the United Nations Global Strategy for Plant Conservation has set the goal of ensuring that 75 percent of the world’s threatened plants are maintained in such collections by 2020.

Wallace surveyed more than 3,000 conservation experts to begin developing a catalog of exceptional, threatened plants that are native to the U.S. and Canada, along with the experts working to preserve each species. Some 289 plants have been identified so far for a future database, which she hopes to expand to a global list.

Building on Wallace’s presentation, Gary Shanks captured the audience’s attention with a grim statistic from the International Union for Conservation of Nature. “Over 10,000 plant species are threatened with extinction, which is quite scary,” he said.

According to Shanks, more than 100 plant species are believed to have gone extinct since the turn of this century, and several species now rely entirely on human cultivation for their survival.

In a survey of more than 1,300 horticultural institutions around the globe, he found that over half the respondents are working to re-introduce plants with low genetic diversity.

Some successes have been achieved. Although Erica verticillata, a hardy shrub with pink tube-shaped flowers, was believed to be gone forever from Shanks’ native South Africa during the first half of the 20th century, a few specimens were discovered in the 1980s in parks in South Africa and botanic gardens in Europe. The plant has since been re-introduced back into the wild at a nature reserve in Cape Town.

The American chestnut tree, which has been the focus of research and restoration in the U.S., could serve as a flagship for the preservation of other species, Shanks said. Several disease resistance genes — from wheat and from the Chinese chestnut — currently are being studied to enhance the American chestnut’s ability to defend itself from blight.

Shanks traveled more than 7,500 miles from Cape Town to participate in the Longwood Graduate Program, which was highly recommended by Martin Smit, a program alumnus. Smit is curator of Stellenbosch University Botanical Garden in South Africa.

A closer look at public garden operations

Other Longwood Fellows focused on public garden operations ranging from visitor education to plant sales.

Felicia Chua, from Singapore, surveyed visitors to Phipps Conservatory in Pittsburgh to find out what interpretive approaches — from brochures, displays and self-guided tours to social media and QR codes — are most effective in motivating the public to learn more about sustainability.

Her survey, which she says other gardens may adapt, is in the appendix to her thesis, which will be available from the University of Delaware Library in the future. Chua will return to Singapore to channel her new knowledge into the Gardens by the Bay, which she helped to create.

Bryan Thompson-Nowak explored how three representative sites – including a college campus, native woodland garden and research collection – handle tree care, a typically expensive task. Through case studies at Moravian College in Bethlehem, Pennsylvania, the New England Wildflower Society Garden in Framingham, Massachusetts, and Montgomery Botanical Center in Coral Gables, Florida, he illustrated how mutually beneficial partnerships between public gardens and arborists/commercial tree care companies can be developed. He is now the assistant director of education and outreach at Morris Arboretum of the University of Pennsylvania.

A self-professed “late bloomer,” Sarah Leach Smith, from Durham, North Carolina, worked in publishing before pursuing her passion for horticulture. She found that commercial growers are slowly phasing out trial gardens. She recommended that public gardens form partnerships with local nurseries and independent garden centers to develop trial gardens and to boost consumer awareness of what these gardens show: what will grow well in consumers’ own backyards.

Kevin Philip Williams, a native of upstate New York, took a closer look at special event plant sales and found that although they may not always be major fundraisers for public gardens, these events can support other important goals such as increasing memberships. Giving staff greater ownership of event planning, expanding volunteer support, and pursuing sponsorships for food to shopping carts can make plant sales more manageable, and they can be “weatherproofed” by holding them indoors, he said.

Video of the fellows’ presentations is available here. The next cohort of Longwood Fellows will begin their studies in July. For more information about the program, visit the website.

Article by Tracey Bryant

Image courtesy of Longwood Graduate Program