Horticultural therapy, as an emerging mental health intervention approach, enhances people’s physical and mental well-being through interaction with plants. In response to the frequent occurrence of psychological problems among college students, horticultural therapy can play a positive intervention role. However, the application and practice of horticultural therapy in professional courses are still in the initial stage. This research draws on the horticultural therapy practice project at the University of Tennessee in the United States and the Five Senses garden design practice at Tsinghua University as examples to explore the application of horticultural therapy in higher education and its positive impact on mental health. This study examines the psychological challenges faced by college students today and then explores an innovative educational model that integrates horticultural therapy with professional courses, using case studies. Takes “Creative Garden Construction” as a starting point and integrates horticultural therapy into the participatory design course at the university, establishing a teaching philosophy that emphasizes humanistic care, constructing an interdisciplinary innovative teaching model, developing participatory teaching resources, summarizing the practical approaches of integrating horticultural therapy into professional courses, and providing reference and inspiration for related professional course reform.