Dr Nicolson Siu on healing through gardening


While it might seem obvious that being outdoors in nature is good for the body and mind, neuroscientist and psychologist Dr. Nicolson Siu tells us that gardening has demonstrably effective therapeutic applications.

Sitting in the lush, green park surrounding the Hong Kong University of Science and Technology (HKUST), neuroscientist and psychologist Dr Nicholson Siu gazes out over the bays, mountains and islands of the New Territories in the North East. From this distance, with the wind of a mid-June thunderstorm blowing through the trees and bands of rain sweeping across the distant hills under slate gray skies, the scene looks untouched, bucolic and even elemental. But what we can’t see a few miles behind us are the tight towers of one of the most densely populated places on Earth, the vast majority of whose inhabitants have little or no contact with the nature. And it’s a problem the young academic is determined to do something about.

Dr. Nicholson Siu

After studying psychology as an undergraduate, Siu had pursued a doctorate in neuroscience at the Chinese University of Hong Kong, where for his thesis topic
he studied the cognitive functions and executive dysfunctions typical of autism spectrum disorders. Now a lecturer at HKUST, he has also become an expert on the subject of horticultural therapy, a topic he discovered while researching for his thesis.

“I was thinking about how we could help these kinds of kids,” Siu says sincerely, clearly passionate about his work with autistic children. “I was researching different kinds of alternative and complementary therapies, and I came across a book called The Last Kid in the Woods.”

Written by American journalist Richard Louv and published in 2005, The Last Child concerns the widespread disconnection with nature in Western and urbanized societies, where children now prefer to play near electrical outlets rather than go outside. (As was already evident for Louv in the mid-2000s, several years before the widespread use of smartphones, tablets, social media, games and streaming online entertainment, not to mention two years of semi-lockdown , one can only conjecture how much more ingrained this trend is today.) Although Siu says the writer’s idea was not a formal diagnosis, the doctoral student at the time was particularly enamored with the book’s theory of “nature deficit disorder,” a condition linked to inattention, depression, and even criminality. And it sent Siu on her own journey which ultimately led to her discovery and subsequent interest in horticultural therapy. Today, he not only lectures at HKUST, but is also vice-president of the Hong Kong Horticultural Therapeutic Association (HKATH), the city’s leading body promoting the principles, goals and uses of horticultural therapy; the association also offers professional courses for future professionals and practitioners on various aspects of the subject.

Horticulture Therapy Gardening

Now increasingly used in the treatment of a number of disorders, from young people on the autism spectrum to elderly patients with dementia, in addition to well-known prison programs for the rehabilitation of offenders (in which participation has been shown to significantly reduce depression and boost self-esteem), horticultural therapy is by no means new, although its current – and growing – popularity dates back to the last 50 years. “There is a long history of herbal healing, which we can trace back at least to ancient Egypt,” Siu tells me. “We know there was horticultural therapy – or gardening therapy – through paintings on the pyramids, which record patients walking through the garden to relieve mental health issues.

“In the last century, it gained official recognition in the 1970s in the United States, when the first degree course in horticultural therapy was established and the American Association for Horticultural Therapy was formed. It is now recognized as an alternative and complementary therapy.

As an adjunct to medical treatments, horticultural therapy can be used as a complementary therapy for cardiovascular disease and stroke. “We’ve found that it helps patients build self-esteem and become more confident, able to do what they want to do and have the ability to do it,” says Siu. “Its uniqueness lies in the fact that you interact with living plants and through them you receive metaphors for the meanings of life – the life cycles of plants are similar to those of humans: you have birth, growth, troubles , you grow old and finally there is death. It is a metaphor for human life. So we use these strategies to enlighten our clients. And unlike other types of therapy, like music or art, horticultural therapy involves interaction with living entities.

“The interaction with plants also involves stimulating the five senses: smell, sight (color), touch (different textures), taste – because you can try different herbal teas or something like that. And then there’s the sound, because when we take guests outside, they hear the wind in the trees, the chirping of birds and the water flowing. There is a lot of research showing that if you take patients outside it increases sensory stimulation and that in turn aids in their recovery, whether they are stroke victims, patients with depression or people suffering from motor dysfunction, helping them a little to resume physical activity.

Whether or not you are undergoing treatment, the notions that being outdoors in nature is good for the mind as well as the body are clearly long-held and deeply rooted. Otherwise, why would medieval monks create cloisters and gardens as aids to solitary contemplation, or Victorian reformers so enthusiastically laid out parks as – at least temporarily – respites from the monotonous daily grind of the mines, mills and factories of the industrial revolution? However, as Siu tells me, the idea that interacting with plants is mentally and physically beneficial is something that is supported by laboratory research.

Horticulture Therapy Gardening

“Studies show that secretions of neurotransmitters, like serotonin and dopamine, are released during physical activity – and horticulture, especially when done outdoors, can be quite a demanding form of exercise. “, he says. “There are also studies showing that there are bacteria in the soil – mycobacterium vaccae – that can stimulate the secretion of serotonin, which affects mood, sexual function, memory, sleep, appetite and even the social behavior, and is often used as a medicine for patients with depression.You are exposed to this antidepressant soil microbe just by getting your hands dirty!So this strongly supports the idea that horticultural therapy can really help them.

“The other important neurotransmitter linked to horticulture therapy is dopamine, which has the potential to convert into epinephrine, which can help give you feelings of euphoria in a natural way, similar to how exercise releases endorphins. In this case, it’s related to the happiness people feel when they see their crops grow – and, eventually, when they’re able to harvest and eat them, which is obviously a pleasurable experience for them. many of our customers, it seems that when you hunt and gather, as well as harvest vegetables and flowers, you get a nice dopamine boost.

As a farewell, Siu cites some of her own experiences with children on the autism spectrum, who are eager to share with their parents their happiness about the vegetables they have grown. “It was an amazing experience for me in my own research, when I discovered for myself how horticultural therapy can help so many different types of people,” he says. “It not only brings children to the factories, but it also opens up horizons for them and helps them to be more willing to try new experiences. People with autism spectrum disorders often prefer closed situations, but it can help them become more open-minded.

“In one case, some parents even rented a field so that their children could continue their planting activities after the program ended. One told me that after horticultural therapy, they took their daughter to Disneyland. She once didn’t want to ride the rides, just went to the bathroom where she stood in the corner, but this time she actually asked if she could go on the roller coaster. We obviously can’t show if there is a direct correlation, but his parents were certainly very happy!



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