Studies called horticultural therapy are being conducted by physicians (Horticulture as Therapy: A Practical Guide, Mitchell L. Hewson, 1994). They are convinced that gardening helps to heal their patients not only physically but also emotionally. Horticultural therapists have discovered that gardening allows patients to better express their emotions. It helps people to bind more easily to others. The psychological benefits to simply walking outside or working under the sun in fresh air are also indisputable. Indeed, studies have shown that simply watching the trees reduces stress, lowers blood pressure and relieves muscle tension. Horticultural therapists have found that gardening stimulates all senses providing views, sounds, textures and interesting perfums for individual development. In addition, gardening teaches the art of patience. In contrast to other activities, it does not produce instant results, but patience is often rewarded.