"Horticultural therapy is defined by the American Horticultural Therapy Association as the “participation in horticultural activities facilitated by a registered horticultural therapist to achieve specific goals within an established treatment, rehabilitation, or vocational plan” . Existing evidence suggests that horticultural therapy provides physical, cognitive, social and psychological benefits for a variety of populations, including individuals who have mental health issues such as trauma, PTSD, depression, anxiety, schizophrenia, and alcohol and drug abuse. In one peer-reviewed study, the task of gardening for as little as 30 min was shown to reduce salivary cortisol levels and improved the moods of participants, suggesting that gardening can reduce stress levels in individuals. Cortisol levels were also shown to be reduced in older adult populations when spending time in a garden . Other work shows that interactions with plants and nature have a positive effect on an individual's overall well-being . A recent study indicates that the quality of the natural area and designation status has an impact on enhancing psychological restoration. Further, this  study suggests that interconnections between life, such as plants and humans, has a positive impact on an individual. This is defined by the term biophilia, or “the innate tendency to focus on life and lifelike process, to the degree that we come to understand other organisms, we will place greater value on them, and on ourselves".


Complementary Therapies in Clinical Practice, 2018-08-01, Volume 32, Pages 74-78, 2018 Elsevier Ltd