April 16, 2024 — Ask any garden enthusiast, and you’ll hear how grounding it is to connect with plants and the Earth. Spending time with nature is widely thought to boost mental and physical health, and nurturing your own flora brings many people feelings of calm, connection and confidence. Increasingly, doctors and therapists around the U.S. are recommending therapeutic horticulture to patients of all ages to help improve symptoms in a variety of illnesses, from anxiety and depression to Parkinson’s disease.

University of Florida College of Medicine, UF Health Shands Arts in Medicine and College of Agricultural and Life Sciences researchers at Wilmot Botanical Gardens have found empirical evidence supporting the benefit of therapeutic horticulture for healthy women in a study aiming to establish a baseline for true treatment effects.

“I like to say this is a therapeutic approach that is hiding in plain sight that we still have not scientifically characterized to the fullest,” said Charles Guy, Ph.D., a scientist with Wilmot Botanical Gardens’ therapeutic horticulture program and a professor emeritus of plant physiology and biochemistry at the College of Agricultural and Life Sciences. “There’s a very, very large body of anecdotal information about the effects of plants, being in nature, connecting with nature, those kinds of things. What we’re really trying to do is understand the magnitude of effects that doing these kinds of activities have on people.”

In a study published in the journal PLOS ONE on July 6, 2022, the interdisciplinary group of researchers examined the effects of therapeutic horticulture versus art therapy in healthy women. Participants in each group met for eight sessions, where they socialized with other group members and performed activities like planting seeds, propagating and harvesting plants, and art-making.

Results showed both therapeutic horticulture and art therapy were beneficial, with gardening having a slightly larger impact. Study subjects experienced a reduction in symptoms of depression, perceived stress, anxiety and mood disturbances.

The authors also found evidence of a dosage effect, where attending more sessions resulted in greater therapeutic benefit to participants.

“When you have a headache, you want to know what dosage of painkiller you can take and how often you can take it,” Guy said. “We wanted to know whether a single session of horticulture or art activities would have an effect and what would happen over four, six, eight treatments.”

Elizabeth Diehl, M.L.A., director of the Wilmot Botanical Gardens therapeutic horticulture program, added, “I have worked with many groups of people in programs addressing different challenges, and eight sessions is usually a minimum. This is especially true if we are working to improve functioning or change behavior.”

Craig Tisher, M.D., director of the Wilmot Botanical Gardens and former dean of the College of Medicine, said this sort of foundational study would not be possible without the rich history and expertise in therapeutic horticulture at UF. In 2011, when Tisher was restoring the gardens, he and other university faculty made the important distinction that Wilmot Botanical Gardens would not just be a beautiful space on campus for students, employees and the public to enjoy time in nature — it would also be an important venue to address patient care.

What began with a small group of veterans and a potting shed on campus has now expanded to award-winning, rigorous science at a state-of-the-art facility with extensive grounds and its own greenhouse.

“I’m especially excited about the fact that the study received the 2023 Charles A. Lewis Excellence in Research Award from The American Horticultural Therapy Association,” Tisher said. “I regard this as very important because it was judged by the people who are thinking about this discipline every day, and they felt our study was well-controlled, well-executed and important to the literature currently available in horticultural therapy and protocols.”

The study was also recognized by the UF Institute of Food and Agricultural Sciences, or IFAS, as a High Impact Research Publication, the first time to Guy and Diehl’s knowledge that IFAS has given this honor to a research project about the psychological impacts of plants on people.

“Therapeutic horticulture could be another significant tool in the toolbox of health care professionals to say, ‘this is another way we can help people feel better and actually improve the overall health status of our populations,’” Guy said. “Our study clearly shows the potential therapeutic benefits. What we need is to expand this.”

Moving forward, the group hopes to continue studying therapeutic horticulture, possibly collaborating with other programs at UF as well as universities around the U.S. Where plants thrive, so does healing, and further research could help better determine benefits to patients.

Tisher noted that plans are underway to construct an outdoor therapeutic horticulture garden with 3,000 square feet of space adjacent to the Wilmot Gardens greenhouse. This new venue will allow university staff to serve a larger and more diverse population of individuals, to enhance the current curriculum by adding outdoor gardening activities and to expand the research program.