Dr Menninger, founder of the Menninger Clinic in Kansas, established the tradition of using nature and gardening in hospital care (Horticultural Therapy). In 1942 he stated the following:

Peonies are very healthy flowers, they have no aches and pains, they make no outcry and there are no anxious and troubled faces to comfort. They just grow and bloom. That is why I fall more and more in love with them. They have helped me to keep my emotional and intellectual equilibrium. Growing peonies has helped me to satisfy an inborn curiosity to watch things grow. There is gratification of the sense in colour and colour combinations, of the sense of smell in perfumes and odour and to that inner aesthetic sense of beauty and charm that has, I believe, made a better physician of me. My whole nature improved, my horizons widened and my appreciation increased in a way that aided me in my vocation. Hope never dies in a real gardener’s heart. Thousands of scientists have chosen horticulture as a hobby and are better for it.”

The Menninger Foundation and Kansas State University started the first student horticulture therapy program in 1971. The two institutions continue to work together to this day.