According to Dr. Karl Menninger, founder of the renowned Menninger Foundation, "[Horticultural therapy] is a kind of adjunctive therapy which brings the individual close to the soil, close to Mother Nature, close to beauty, close to the mystery of growth and development. It is one of the simple ways to make a cooperative deal with nature for a prompt reward."
With support from the Menninger Foundation, Kansas State University started a Horticultural Therapy Program in 1971. "Research on the people-plant connection has yielded only positive results -- no matter if the plant life is a single flower on a desk or a group of trees in a botanic garden," said Dr. Richard Mattson, program coordinator.
"Just walking through a garden can reduce blood pressure," Mattson said. "If you pick up and use a shovel or hoe, you gain strength benefits. If you use those tools with some enthusiasm or determination, you also get aerobic benefits similar to those in jogging or working out with exercise equipment."
I'm not surprised. Personally I find that working outside with plants is extraordinarily satisfying. However, my real skill seems to be landscape reduction rather than planting. When I'm feeling the slightest bit low, I get out my clippers and work on some major project like trimming the Eugenia trees or cutting back the bougainvilla.
While my husband excels at planting, innately knows which flowers look best together, and has grown some delicious beefsteak, heirloom, and cherry tomatoes, I am best at pruning, cutting, paring, snipping, shearing, reducing, thinning, and eliminating. For some people, this type of "horticultural therapy" may not be be considered a wellness activity but it is for me.