Research shows that a sensory blast from a richly diverse green space does wonders for stress levels.
Now, it seems these sorts of environments may be affecting the health of those who live in towns and cities.
During a long career as a landscape designer, Auckland’s Gayle Souter-Brown has travelled the world creating sensory gardens for people in need. It is well recognised that spending time surrounded by the scents, textures and colours of nature benefits those with conditions that range from depression and dementia to post-traumatic stress disorder, addiction, serious head injury or autism.
What Souter-Brown began to wonder is whether everybody would be better off regularly spending time in a garden designed to appeal to all the senses.
There is already some interesting research on the subject. For instance, at the University of Queensland, Danielle Shanahan led a study that identified the required dose of nature for human health and well-being as being a minimum of 30 minutes a week. And new US research shows that to get a significant reduction in stress, we need to spend 20 to 30 minutes a day in a space that provides us with a sense of nature.
But does a plaza-style space count as nature? Or do we need something more verdant to enhance our well-being?
Souter-Brown designed her own study to find out. It involved building a sensory garden based on one she had visited at a Swedish agricultural university. Created to offer nature-based rehabilitation for individuals with stress-related mental illness, the Swedish garden has a profusion of plants, trees and shrubs.
At the Auckland University of Technology Northcote campus, Souter-Brown set about transforming a neglected 900sq m plot of land. The garden she created is ecologically diverse. There are vegetables and berries in raised beds, scented flowering plants such as daphne and sweet peas, areas designed for quiet contemplation, woodland and wildflowers, pathways and seating.
“We were lucky enough to have existing mature trees, a little waterfall and a pond,” she says.
A lot of effort went into building the garden, with friends and family pitching in.
“I didn’t think I was going to finish it in time,” says Souter-Brown. “My in-laws, who are in their eighties, were out digging in the rain the weekend before we went live, and my husband, son and daughter all spent hours helping. It was quite an undertaking.”
Souter-Brown divided the 164 participants in her study into three groups. One group spent 30 minutes a week relaxing in her sensory garden, another spent a weekly 30 minutes in a plaza space and a control group did their normal outdoorsy activities such as walking the dog.
Participants’ levels of the stress hormone cortisol were then checked and they were asked how the experience had affected their sense of well-being and productivity.
Souter-Brown is still working through the data, but some interesting results are emerging. “As you’d expect, the control group stayed roughly the same,” she says. “The cortisol levels of the people in the plaza group dropped about 6%. And the levels of those who’d had the experience in the sensory garden dropped by 20%.”
Just having time outside breathing fresh air and relaxing lowered stress levels. But the group who could wander about listening to birdsong and seeing what had come into flower or fruit were better off.
When asked to measure their own well-being, the sensory-garden group reported feeling better, whereas those in the plaza felt their well-being had diminished and productivity dropped. “So we can say that the plaza did measurable harm,” says Souter-Brown.
With chronic stress linked to a host of health issues – including heart disease, anxiety, depression, digestive problems, headaches and weight gain – Souter-Brown believes she is making a strong case for more richness and diversity in our public spaces and our own backyards.
“Aim for species richness and choose plants that will be attractive to butterflies, insects and birds,” she advises. “Rounder leaf forms and flower petals are more relaxing than the harder-edged spiky forms. But the most important thing is to take time out and put nature back into our lives.”
This article was first published in the April 27, 2019 issue of the New Zealand Listener.