The Quest for Rare Plants: Meet Mercer's Plant Hunters

story and photos by Crystal Simmons

Long before orchids became America's best-selling houseplant, they enchanted generations of Victorian-era Europeans willing to pay a premium for the exotic import. Beautiful, fragile, and, most importantly, exclusive, New World orchids rivaled art, fine wine, and even precious stones in their collectability.

Unfortunately, the only way to find such a species was to fund expensive orchid-harvesting voyages to the forests and jungles of North and Central America. The result was disastrous. Plant hunters robbed entire ecosystems of the plants and nearly ended their occurrence in the wild.

As perspectives on plant conservation changed, researchers, conservationists, and botanic gardens banded together to set new standards for acquiring rare plants. Vast networks of botanic gardens arose, and strict permitting laws now regulate collecting plants in the wild.

As a result, some of the world's rarest plants now inhabit public spaces like Mercer Botanic Gardens, a 400-acre greenspace with 4,000 different kinds of plants, including 128 species that are rare or endangered.

"Botanic gardens trade a lot of rare plants with each other for backups," says Jacob Martin, the greenhouse manager at Mercer Botanic Gardens. "The first thing we usually do when we receive a rare plant is to make a backup for ourselves and then share backups with other botanic gardens so the plant is never lost."

Martin is part of a new breed of plant hunter who works to preserve rare and unusual plants. He often heads into the wild to collect seeds from edibles and plants found in jungles, forests, deserts, prairies, and coastal regions. This passion for wild plants has inspired him to take at least eight seed-collecting trips to areas including Ecuador, Costa Rica, and West Texas.

Memorable finds include two popular species, Amazon coral tree (Erythrina amazonica), a tree from Ecuador dripping with hot pink, pointed blooms, and a wild papaya tree Vasconcellea cauliflora) in Costa Rica. Both are now growing in Mercer's Tropical Garden.

“We grow a lot from seed so it acclimates to our region as it grows,” he says. “If I buy a plant from Florida, it needs to make entirely new leaves to be like Texas leaves. If it grows here from seed, it has a better chance of developing heat tolerance.”

Martin also seeks rare plants from commercial growers like Plant Delights and Far Reaches Farm, businesses that work directly with botanists and botanical gardens to sustainably collect seeds in the field.

“There are a few nurseries around the country that sell rare plants, and they do quite a lot of wild collecting,” says Martin. “If we need something, we can usually find someone with seeds.”

A great example of this partnership is Woodfordia fruticosa, a heat-loving woody shrub with sunset orange flowers that usually only grows in parts of India and the Middle East. Because of India's tightly regulated plant trade and the difficulty of growing the plant from seed, Woodfordia fruticosa is hard to find in the United States. Despite its scarcity, Martin stumbled upon the plant two years ago online.

"It bloomed the first time this year," says Martin. "You probably won’t see this anywhere else in the United States. We only have it because we were able to grow it from seed."

SPECIALTY GINGERS

Ceil Dow, a ginger enthusiast, master gardener, and Mercer volunteer, has spent three decades forming partnerships in the gardening community and identifying the best ginger specialty nurseries. She uses this knowledge to secure new gingers for Mercer's collections and plant sales hosted by The Mercer Society (TMS), the nonprofit supporting the gardens.

“After the ginger garden was remodeled and then damaged by the impact of Hurricane Harvey’s lengthy flooding, a number of gingers were lost,” she says. “I have kept old records and maps of the gingers in the garden and was able to add plants from my collection. My collection has grown to about 140 varieties, so I am still finding that I have a plant or two to add.”

Since becoming a Mercer volunteer, Dow has donated 25 gingers to Mercer's collection, including the rare dancing lady ginger (Globba globulifera) that is native to Thailand. TMS has donated a similar amount, bringing Mercer’s collection to 150 types of gingers, including many scarce varieties.

"If we come across a ginger that the gardens do not have, then The Mercer Society tries to donate it," she says. "It is huge fun to find some hard-to-find plants or plants that haven’t been around for a while."

CONSERVING RARE PLANTS

At the heart of plant collecting is the desire to increase plant diversity. By sharing rare and native plants, botanic gardens around the world ensure that certain species persist.

As Mercer's lead botanical researcher and botanist, Anita Tiller is part of this effort. She maintains a native seed bank and a rare and endangered native plant collection through the Center for Plant Conservation (CPC), a network of 63 botanical gardens, arboreta, and organizations working to promote plant diversity.

"Mercer is responsible for nearly 30 plant species in the CPC's National Collection of Endangered Plants, but we shelter many other CPC plants as backups for our partner institutions," she says. "Some of these plants are displayed in Mercer's Endangered Species and Native Plant Garden for the public to view."

Finding an endangered species isn't always easy, though. If the plant is scarce, someone must head out into the field and collect wild seeds or propagation material. Wild collectors may be volunteers, researchers, students, or government employees.

The elusive Texas screwstem (Bartonia paniculata ssp. texana), a diminutive member of the Gentian family and now part of Mercer's CPC collection, evaded collectors for years until sharp-eyed botanists from the Botanical Research Institute of Texas in Ft. Worth spotted it during a native plant status assessment.

“This annual plant does not regularly make an appearance in the sites where it has been observed," says Tiller. "Separating the tiny dust-like seeds from the seed capsules is a challenge, and our initial germination trials have yet to produce seedlings. Still, we are optimistic."

Plant rescues and donations also make up a sizable chunk of Mercer’s collection. As a Plant Rescue Center for the U.S. Fish and Wildlife Service, Mercer receives plants that were illegally smuggled into the United States and seized at airports or other ports of entry. One of the more recent rescues includes an endangered cycad from Mexico with sharply serrated leaflets. The plant is so rare that Mercer staff l do not reveal its location or label it for fear of theft.

“Cycads are on the top list of plants stolen from botanic gardens,” said Tiller. “Due to theft, some botanic gardens, such as Fairchild Tropical Botanic

Garden, microchip their cycads because so many have been stolen from their collections.”

Mercer has also received donated orchids, houseplants, and most recently, two critically endangered Microcycas calocoma cycads, plants that number less than 4,000 in the wild. Not only is the plant scarce, but it's also hard to collect, growing naturally on cliffs and difficult-to-find areas in a small region of western Cuba. As a result, immature plants cost approximately $250, and mature plants go for much more.

Once Mercer receives a rare plant, people like Martin care for it while Mercer’s curators work to enter the specimen into a database shared with botanic gardens around the globe.

"Texas is home to approximately 400 species of plants that are only found here," says Tiller. "Research and conservation efforts at botanic institutions like Mercer are vital for their survival. Our work at Mercer Botanical Center ensures other botanic institutions are aware of our inventory and have access to it for research and restoration."

Mercer Botanic Gardens works with a variety of organizations dedicated to improving plant diversity around the globe, including Botanic Gardens Conservation International. BGCI is the largest network of botanic gardens and plant experts in the world, with more than 625 members working to promote plant diversity. The organization features the only searchable global database of plant taxa and a plant exchange network for botanic gardens.

BGCI KEY NUMBERS

• 30% (105,634) of all landdwelling plant species are maintained in botanic gardens.

• Approximately 41% (28,873) of threatened land-dwelling plant species are conserved in botanic gardens.

• 20% (70,423) of land-dwelling plant species are threatened, although recent estimates show that this number now approaches 80,000.

• The 625 institutional members of BGCI have collectively raised more than 375,000 rare and threatened seedlings.

Learn more about their work at www.bgci.org.