Horticultural therapy (HT) is the engagement of a person in gardening related indoor activities by a trained professional to achieve specific treatment goals. It was effective as an alternative medicine and played an important role in rehabilitation of stroke patients, especially in psychological aspects. While the psychological benefit has been clearly demonstrated, the evidence of the physical benefit is insufficient. We report three stroke patients treated with HT and they were evaluated from the standpoint of physical, psychological, and cognitive outcomes. HT program consisted of 10 sessions during 2 weeks with 1 hour per session. The assessment of outcomes and positron emission tomography/computed tomography (PET/CT) were performed before and after treatment. Two patients showed improvements in physical and psychological aspects. But the other patient showed no outstanding outcome. These results suggest the possibility of HT as a complement to conventional occupational therapy.