Much of the research surrounding therapeutic horticulture focuses on the connection between the emerging field and its larger application and possibilities within the structured world of medicine.
Those practicing within therapeutic horticulture are actively moving to validate their work in the eyes of western medicine. This movement is carried forward by practices such as accreditation, licensing, research, and publication. While the movement to make therapeutic horticulture a "valid" medical therapy is important, it's also important to not forgo the more broad-based appeal and accessibility that is inherent in this practice.
The Weed Out Hate campaign is a great example of the basic concepts of therapeutic horticulture being applied in a more broad-based manner. The global campaign uses gardening as a way to teach children to root out hate while planting seeds of peace, love and respect. The physical act of pulling weeds out of the ground and planting sunflower seeds in their place is used as tangible symbolism for showing kids the importance of pulling weeds of hate and anger out of their own lives and planting seeds of promise for a better tomorrow. While this obviously wouldn't fit a "medical" description for therapy, I can't imagine any greater way to apply the basic concept of therapeutic horticulture.