Diane Relf, Professor of Horticulture

Originally published in Rehab. Lit. 42:147-150, 1981.

January1996 Authors note: Since the article was published, a tremendous amount of research has been conducted, particularly in passive response to plants. For more information, see Horticulture Therapy research and Human Issues in Horticulture research.

Gardening is perhaps one of the oldest healing arts; yet as a science, it is very new among the therapeutic professions. At this time, very little research data has been accumulated to substantiate the observations made by professionals using plants to help people in distress. However, as a result of repeated successes of practitioners, horticulture is being widely accepted as an effective therapeutic tool. As horticulture is used increasingly in a variety of therapeutic settings, understanding of its value and the mechanisms by which it works improves. As theories are developed and explanations of observations are made, scientific research will become an integral part of horticultural therapy programming.

Observations by professionals can be utilized effectively to analyze the current understanding of the mechanisms by which horticultural activities bring about beneficial change. For purpose of discussion, these mechanisms can be divided into three categories: (a) Interaction, which is concerned with how people interact within the horticultural setting, (b) Action, which is concerned with persons actively working with plants, and (c) Reaction, which is concerned with peoples' response to passive involvement with plants.


According to Charles Lewis (12) of the Morton Arboretum, the plant world is nonthreatening and nondiscriminatory. In a study by Rachel Kaplan (7), a majority of the respondents gave "peacefulness and tranquility" as the most important satisfactions gained from gardening. Ira Stamm and Andy Barber (16) of the Menninger Clinic report a reduction in tension and anxiety in horticultural programs that enhances the patient's receptiveness to being approached by another person. Thus, it appears that working in a horticultural setting provides an atmosphere in which it is easier for people to relate to one another.
There are three types of interactions that may be important in successful treatment programs: therapist-client, client-client, and client-nonclient.
In the therapist-client relationship, the plant world may be used to establish a nonverbal relationship to open communications on subjects that the patient finds extremely threatening, or to face and deal with subjects with which the patient may not be consciously aware are disturbing in nature.
According to Stamm and Barber, in the more severe emotional disturbances, such as schizophrenia, patients often have a long-standing fear of people that is believed to have developed at a point in their lives before words were used to communicate. They report that the "task orientation of horticultural therapy is ideal for such a patient, for it allows him to enter gently into a relationship with another person in a non-verbal way without the threat of being confronted with interpersonal closeness too soon as may occur in a one-to-one verbal psychotherapy." (16)
Two subjects that in many contexts are perceived as threatening are death and sex. However, death--whether a flat of seedlings lost to damping-off or a flower fading from its peak of beauty--is an integral part of horticulture and must be dealt with on a continuous basis. Likewise, plant propagation, both sexual and asexual, is a part of many horticultural activities. Encountering these topics in horticultural therapy may bring forth opportunities for discussions that can ultimately lead to communications and insights in the far more complex areas of human death and human sexuality.
Appropriate interaction between patients or clients can be an essential step toward their integration back into the community or certainly toward a fuller, more socially active life within an institution. In the psychiatric setting, Stamm and Barber agreed that the more developmentally mature patient may benefit from a group task in horticultural therapy. This provides the opportunities for emotional growth found in most group settings: the chance to work as a member of a team, to experience sibling rivalry and other competitive feelings, and to experience group support as well as confrontation.
At Melwood Horticultural Training Center in Upper Marlboro, Md., a vocational center for mentally retarded young adults, the clients are taught appropriate interaction for work time and for social or break time. Lack of appropriate behavior with other employees is often a cause for loss of jobs in the community. As clients learn to interact with their peers, they are given more responsible leadership roles. First, they may act as partners to new clients by teaching basic skills. Later, they may become crew leaders over four to five clients in various work situations. (3)
In working with clients who have specific problems in interacting with others, the therapist can structure horticultural activities to provide the ideal setting for acquiring needed social skills. For example, the potting up of house plants can be an individual or isolated activity. It can also be a parallel activity where two individuals work beside each other but are independent of each other in responsibilities. Or, it can be a cooperative activity in which three or more persons have defined roles that are dependent on the others: one fills the pots with soil, one inserts the plant, and one waters the pot. Each must complete this task for the others to continue.
Successful interaction between patients or clients and the rest of the community is critical for persons with disabilities to function at their highest level. The nature of the interaction may vary considerably from one program to another.
At Melwood, mentally retarded young adults raise foliage plants in a modern greenhouse. These are taken to plant sales in the lobby of various federal buildings in Washington, D.C. While the public shops, they make positive comments about the high quality of the plants. These comments not only enhance the retarded person's self-esteem, but also reinforce the public's increasingly positive image of the abilities of disabled people.
Rhea McCandliss (13) of the Menninger Foundation Clinic in Topeka, Kansas, reports that over the years the Clinic's vegetable garden served a variety of community needs: help in feeding flood victims, providing the vegetables for emergency kitchens, feeding tornado relief workers, and supplying tomatoes to the adult's and children's hospital as well as several youth homes in Topeka. Dr. Will Menninger writes, "as they share the product of the work with people less fortunate economically, patients picture themselves often for the first time as productive members of society." (15)
Horticulture provides opportunities for human relationships by providing common interests, shared experiences, and opportunities for competition. A well-cared-for plant entered in a local flower show will have an equal chance of winning regardless of any impairment its grower may have. People do like to compete and plants are an equalizer among people.
The potential interactions between individuals are limitless. The interactions can be ones that naturally evolve from a situation and allow the patient the opportunity to explore new relationships, or they can be structured and guided by the therapist to reach a desired goal.

Action: Working with Plants

The essence of horticulture is action. Man as a gardener is active, he is working with plants doing things with them or to them to modify and enhance their growth. This action of man with plants brings about many of the therapeutic benefits of horticultural programs. One explanation for the positive response that man has to working with plants may be because it deals with life cycles, and most people make a ready translation between the life cycle of plants and their own human life cycle.
In examining the dynamics of horticultural therapy, specific functions and experiences that can be activated and rehabilitated by direct involvement with plants have been identified:
1. Integration of biological and psychological factors. According to Bardach (1) of New York University Institute of Rehabilitation Medicine, newly disabled persons frequently have major problems in integration, an important aspect of which is the relationship of the physical disability to the rest of the individual's personality. According to Bardach, a physical activity that simultaneously deals with aspects of the disability itself, the emotional meaning of that disability, and the possibility that the consequences of the disability are not inevitably dire may foster integration of mind and body. For example, the woman who has paraplegia as a result of a car accident thinks of herself as a helpless cripple who "can't even stand up." In horticultural therapy, she learns to stake the plants and comes to see concretely that she can do something useful. In addition, she experiences three things symbolically: she learns that other things need support, she has an interest in supporting a plant--thereby being useful to another living thing, and she (and by implication, others) feels it is genuinely worthwhile to aid in the support of others who literally cannot stand alone.
2. Mastery of the environment. Persons in a nursing home or a hospital or those with limited ability to leave their homes feel helpless to control their life or environment. Rules and regulations, or simply lack of money, prevent redecoration. However, a geranium in a sunny window may not only brighten the room, it may also act as a signal of individuality. This response has been particularly well-recorded in inner-city gardening programs that have resulted in neighborhood clean-up projects, as the individuals discover that their actions can change their surroundings. (12)
3. Work substitute. According to Levinson (11), when one works, one has a contributing place in society and that work is a major social device for identification as an adult. Unfortunately, many individuals do not have the opportunity to participate in the modern work world, due to disabilities, age, or other limiting conditions. However, horticultural activities can provide a substitute for some of these work needs. By growing a vegetable garden, persons with disabilities may provide for some of their and others' physical needs. Growing flowers can be a gift of beauty to others. The products of growing plants have value that is recognized the same as money and may in fact be sold or traded. In some situations the horticultural activity may lead to self-employment, sheltered employment, or a job in the community.
4. Responsibility. The feeling of responsibility and the dependency of the plant for care are important therapeutic elements for many. In research conducted by Langer and Rodin, (10) one group of elderly residents of a nursing home were given the freedom to make choices and personal responsibility for care of plants. A second group had the decision made for them and the plants taken care of by the staff. The first group showed a significant improvement in alertness, active participation, and general sense of well-being.
5. Creativity. Creativity is a means of self-expression that is often frustrated among the persons with disabilities. Horticulture offers the opportunity for many creative experiences, such as flower arranging, bonsai, and landscaping. On another level, plants also offer a creative experience in life and growth. By making a simple cutting or planting a seed, one creates an entirely new plant. This concept is expressed by Carol Cole, a young heroin addict, writing about her garden as part of her drug rehabilitation program: "It is especially great when we can just sit and watch it all grow in the warm evening, giving a feeling of having accomplished something good." (2)
6. Frustration tolerance. When dealing with living, growing plants, things will go wrong despite the best of plans. Disease, insects, and weeds will take their toll and erratic weather will complicate the problem. Learning to cope with inevitable frustrations in gardening may help prepare the patient to deal with other frustrations in everyday life.
7. Intense concentration. According to Rachel Kaplan, psychologist at the University of Michigan, one of the benefits of gardening is that it is a source of fascination that sustains involuntary attention. (7) That is, gardeners become completely absorbed in their work and do not have to put forth the effort required of voluntary attention; therefore, they have a rest from the normal efforts of the day. Also, since attention by definition excludes other thoughts, gardeners have a break from the normal worries and cares of the day.
While not exhaustive, this list indicates some of the ways in which working with plants has a beneficial effect. In addition, working with plants has a positive influence from a purely physical standpoint. It can provide excellent exercise that is important in toning muscles. At the New York Institute of Rehabilitation Medicine, Jo Ann Hiott (4) reports effective transference of skills as a man with quadriplegia learns to use special tools for potting plants that he can later use to feed himself.

Reaction: Passive Experiences with Plants

The hypothesis has been put forth that man has a basic psychological need for plants in the environment. (6) Little empirical data to support the hypothesis have been collected. However, there is sufficient cause to give some consideration to this theory. Man is physically dependent on plants for food and for much of his shelter, clothing, and energy. Man evolved with plants in his environment. It has only been in recent years that he has spent many hours of the day in buildings devoid of plants. It is not unreasonable to theorize that the environment that has had a significant impact on man's physical, social, emotional, and intellectual development as a species would be one with which he would continue to respond.
In a preliminary report on an extensive study designed to examine the effects of external stimuli on the social behavior of chronic mental patients, Talbot reported that the introduction of flowering plants in the dining room setting was followed by a significant increase in vocalization, time spent in the dining room, and amount of food consumed. The effect was statistically significant even in patients who were severely withdrawn. The explanation for this response was not identified. (17)
At the administrative center of the John Deere Corporation, plants and structure are so integrated as to ensure that no employee is more than 45 feet from vegetation. The leaders of the company report that creativity has been enhanced, productivity increased, and employees voluntarily have upgraded their standard of dress. An explanation of this observed response has not been studied. (12)
However, three possible explanations for man's response to the plants in his environment have been discussed in the literature:
1. Plants serve as a stimulus for a direct, specific, positive response for which the human perceptual system is specifically developed. 2. Plants are a part of the aesthetically pleasing and perceptually stimulating aspects of the environment to which man responds. 3. By observation of plant growth and change, man learns about life and acquires an understanding that can be applied to other aspects of life.
The basis for these explanations comes from observations of scientists and social scientists. The idea that man has a specific response to plants due to the evolutionary development of his perceptual system was put forth by Iltis. (5 )In discussing the co-evolution of color vision and fruit color, he theorizes that improved color vision enhanced identification of colorful fruit as a food source that increased dissemination of seeds of the more colorful fruit types. He goes on to theorize that as color vision improved, and as fruits evolved, there evolved in the mammal brain a pleasurable feeling at the sight of brilliant color. This was inducement to look for food. Gradually, in evolution the aesthetic feeling developed.
Stephen Kaplan theorizes that to survive, primitive individuals had to learn to quickly perceive a situation, determine the best action, and execute it. (9) Landscapes that can easily be read for vital information have a distinct advantage. Rachel Kaplan reports that specific types of landscapes are predictably preferred by a wide range of individuals; these landscapes can be interpreted as having positive potential for providing information. (8) Thus, it would appear that the specific response to plants and the aesthetic response to the environment may have similar origins in man's evolution.
C. F. Menninger, in writing of his peonies, expressed many of the things an individual gains from living in the natural environment:
There is a gratification of the sense of sight in color and color combinations, of the sense of smell in perfumes and odors, and to that inner aesthetic sense of beauty a charm that has, I believe, made a better physician of me. My whole nature was improved, my horizons wider and my appreciation increased in a way that aided me in my vocation. (14)
From being around plants, from observing their growth, man acquires an understanding of life and the rhythms that maintain it. From plants man derives a sense of "dynamic stability through change." Without continuous change, plants could not survive. A plant must flower in order to set seed; it must go dormant to survive the winter. There is a natural rhythm, a time and a season for all things, and nothing can be forced out of its natural order and still survive.
List of References

List of References

1. Bardach, Joan. Some Principles of Horticultural Therapy with the Physically Disabled. Mt. Vernon, Va.: National Council for Therapy and Rehabilitation through Horticulture (NCTRH), 1975.
2. Cole, Carol. Fruits of the Earth. NCTRH Newsletter. 1975. 2:5:3.
3. Copus, Earl. Landscape for Living: Career Training in Horticulture for Handicapped Young Folks. Yearbook of Agriculture. 1972.
4. Hiott, Jo Ann. Horticulture Used in a Short Term Rehabilitation Center for the Physically Disabled. Proceedings of the 6th NCTRH Conference. Mt. Vernon, Va.: National Council for Therapy and Rehabilitation through Horticulture, 1978.
5. Iltis, Hugh H. Can One Love a Plastic Tree? Bul. Ecological Society of America. 1973. 54:4:5-7, 19.
6. Iltis, Hugh H. Nature and Man, Needs. New Horizons from the Horticultural Institute. 1974. 13.
7. Kaplan, Rachel. Some Psychological Benefits of Gardening. Environment and Behavior. 1973. 5:2:145-161.
8. Kaplan, Rachel. Preference and Everyday Nature: Method and Application. In: Stokol, D., ed. Perspectives on Environment and Behavior: Theory Research and Applications. New York: Plenum, 1977. 9. Kaplan, Stephen. Cognitive Maps in Perception and Thought. In: Downs, R. M., and Stea, D., eds. Image and Environment. Chicago, Ill.: Aldine Pr., 1973.
10. Langer, Ellen J., and Rodin, Judith. The Effects of Choice and Enhanced Personal Responsibility for the Aged: A Field Experiment in an Institutional Setting. J. Personality & Social Psychol. 1976. 34:2:191-198.
11. Levinson, Harry. What Work Means to Man. Topeka, Kan.: Menninger Foundation, 1964. (10 p. reprint).
12. Lewis, Charles A. Healing in the Urban Environment: A Person/Plant Viewpoint. B. Y. Morrison Memorial Lecture. Mt. Vernon, Va.: NCTRH, 1978.
13. McCandliss, Rhea. "The Plant/Man/Environment." Paper presented at C. F. Menninger Memorial Hospital Staff Meeting, Topeka, Kan., 1967.
14. Menninger, C. F. Personal observations. Bul. Menninger Clinic. 1942. 6:3:65-67.
15. Menninger, William C., and Pratt, James F. The Therapy of Gardening. Popular Gardening. 1957. 8:54:54.
16. Stamm, Ira, and Barber, Andy. "The Nature and Change in Horticultural Therapy." Paper presented at the 6th Annual Conference, NCTRH, Topeka, Kan., 1978.
17. Talbot, John A. Flowering Plants as a Therapeutic Environmental Agent in a Psychiatric Hospital. HortScience. 1976. 11:4:365-366.