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A Living Collection of Medicinal Plants

Story by
Nancy Joseph

Walk down the aisles and you will come across some familiar names: Echinacea. St. John's Wort. Camphor. Sound like a health food store? It's the University's Medicinal Herb Garden, nestled along Stevens Way, across from the Botany Greenhouse.

Doug Ewing (left) and Keith Possee, working in the Medicinal Herb Garden.

Doug Ewing (left) and Keith Possee, working in the Medicinal Herb Garden. Media credit: Mary Levin

The garden, maintained by the Department of Botany, was established 87 years ago by the UW School of Pharmacy. "At that time, most drugs used in medicine were plant derived, so a pharmacist needed to know not just the name of compounds but also had to do the extractions," says Doug Ewing, manager of the UW Greenhouse and the Medicinal Herb Garden. "Students learned how to harvest and dry, distill, or otherwise prepare the medications."

Through the years the garden continued to expand, housing a wide variety of annuals, perennials, trees, and shrubs. At one point it served as a commercial source of several medicinal plants, when trade barriers with European suppliers caused a shortage in the U.S. At its peak, it was considered one of the finest collections of medicinal plants in the world.

But modern medicine changed that. After World War II, synthetic compounds rather than plant extracts were used in most medications. The garden's value as a pharmacy teaching tool diminished. Faced with budget cuts in the late 1970s, the School of Pharmacy decided to withdraw its support of the garden.

Fortunately for plant lovers, the Department of Botany recognized the garden's value and adopted it in 1979. But with no additional funds to support the facility, the department had to dismiss the garden's staff--two full-time and one part-time-and assign the then--greenhouse manager the task of maintaining the collection. That included sowing and transplanting seeds for annuals, weeding, watering, pruning, labeling plants, and other time-consuming tasks.

Carved monkey in the Medicinal Herb Garden.

The monkeys resting on pedestals in the garden are replicas of carved monkeys from Europe's first botanical garden in Padua, Italy, established in 1545. Media credit: Mary Levin

"There's no way one person could take care of the greenhouse and maintain a two-and-a-half acre garden with more than 600 species," says Ewing. "The Medicinal Herb Garden slipped dramatically. It could have died--dried up and blown away--if not for a group of volunteers who wanted to save it."

The group, known as Friends of the Medicinal Herb Garden, became involved in 1984 and has provided a core of support ever since, volunteering both time and money to maintain the garden.

Today the Medicinal Herb Garden is more than just surviving. It is, in fact, the largest such garden in the western hemisphere. And interest in the collection is growing, both from the public and the campus community. Keith Possee, a volunteer who also works in the garden on a part-time hourly basis, is one of the people most responsible for this turnaround. But the project is still somewhat daunting.

"It's a difficult thing to maintain a living collection," says Ewing. "You must have year-round provision. Sometimes I'm envious of people who maintain collections of books or fossils. You can take a long weekend and not worry about the collection."

No Foraging, Please

Because the garden is for display purposes and some of the plants are toxic, visitors are prohibited from foraging. "These plants are drugs," Ewing explains. "People who wouldn't root around in their neighbor's medicine cabinet swallowing pills will think it's okay to make a salad with plants they are not familiar with. That's scary."

Consider the castor bean, grown for its oil. It looks perfectly innocent, but ingesting the seeds can be fatal. There is no known antidote.

When school groups tour the garden with Ewing, he shares tales of the castor bean and other toxic plants. It is one lesson that even the youngest students tend to remember. "I tell them they shouldn't taste or eat any plant unless someone they trust tells them it's okay," says Ewing. "I also talk about plant diversity and how plants have adapted to their environment."

Madagascar periwinkle

Madagascar periwinkle (Catharanthus roseus) is the source of vincristine sulphate, a chemotherapy drug. Media credit: Mary Levin

For adults interested in touring the site, docents from Friends of the Medicinal Herb Garden offer monthly tours from spring through autumn. The collection continues to evolve, so there is always something new to see.

"We've purged some stuff that's less interesting to make room for new plants," says Ewing. One example is the Pacific Yew tree--the source of the cancer drug, Taxol--which was added to the garden after its medicinal properties were discovered. Possee has added many traditional Chinese Medicine Plants as well.

As Ewing scans the colorful garden, a veritable museum of medicinal plants, he shudders to think what might have been. "This is a mature garden," he says. "A lot of the plants are mature trees and shrubs. If it had dried up and blown away out of neglect, it would be so hard to build it again from scratch. …That would have been such a loss."

To take a virtual walk through the Medicinal Herb Garden or to learn about individual plants, visit the garden's Web site at http://www.nnlm.nlm.nih.gov/pnr/uwmhg/.