Even small, everyday interactions with nature — from a single houseplant to a 20-minute walk through the woods or a garden — can measurably improve our mental and physical health. Biologist Kathy Willis, the author of the new book “Good Nature,” joins me to explore the groundbreaking research revealing how touching, smelling and even just seeing plants benefits our well-being.
Kathy lives in Oxford, England, and is a professor of biodiversity in the department of biology at University of Oxford. Her research aims to understand how plant biodiversity responds to climate change and other environmental drivers. She is internationally recognized for her work and has led a number of initiatives to assimilate global knowledge on plant biodiversity.
Biologist and Professor Kathy Willis’s new book is “Good Nature: The New Science of How Nature Improves Our Health.”
Photo Credit: John Cairns
She is a former director of science at the Royal Botanic Gardens, Kew and has authored or co-authored more than 100 scientific publications, including the landmark book “The Evolution of Plants.” In 2022, she joined the House of Lords — the upper house of the U.K. Parliament.
Her broadcasting work has included writing and presenting on several BBC television and radio programs. She was awarded the Michael Faraday Medal for public communication of science from the Royal Society in 2015.
Meet Kathy Willis
“As a child, I always just liked being outdoors — always — even though we grew up in London, but we grew up in a sort of northern part of London, which is quite leafy,” Kathy recalls.
Her mother was of the generation that was evacuated from Central London to the countryside during World War II. Her mother learned the names of all the plants and was knowledgeable about landscapes.
“That just rubbed off onto me, and whenever we went on holiday, she’d always be pointing out the flowers in the hedgerows,” Kathy says. “And so I got very attached to the environment.”
In school, she gravitated toward biology. “And I also liked geography and I liked chemistry and the interaction of the natural world,” she adds.
She was among the first generation of her family to go to university — at the University of Southampton — and she pursued an environmental science degree.
“That was at the point where people really weren’t thinking about climate change,” she says. “This is 1982.”
The coursework involved spending a lot of time in The New Forest, a beautiful national park in southern England.
Kathy continued her studies at Cambridge, where she earned a Ph.D. in botany, studying how vegetation responds to climate and other environmental drivers. She remained at Cambridge for 13 years, including one year as the plant sciences editor of the Cambridge University Press — but she realized she is not very good at being indoors with books.
“After spending this time at the publisher for one year, I then went back into research,” she continues. “But it was a very good year out because it made me decide what I did want to do rather than just carrying on.”
She next took a job at Oxford teaching geography, but she learned that geography did not include anywhere near as much environmental science as she expected.
“I learned huge amounts about subjects I’d never really embraced before, about human-nature interactions, about landscapes,” she says.
She advanced at Oxford to run a master’s program on biodiversity conservation. From there, Kathy was offered a position as the first director of science at Kew Gardens in London.
“It was a tough job,” she says. “There’s 400 scientists there. I was responsible for all of these major collections, like the herbarium, the fungarium, the Millennium Seed Bank, the molecular records, and the scientists that work on them.”
She returned to Oxford after a five-year sabbatical at Kew Gardens and resumed her research. She is also the principal of St Edmund Hall, a constituent college of the University of Oxford.
A vertical garden on the side of a building. This “living wall” adds a touch of nature to the built environment, which has a positive effect of people’s moods and health in general.
Photo Courtesy of Kathy Willis
‘Good Nature’
“Good Nature: The New Science of How Nature Improves Our Health” pulls together the many different strands of Kathy’s life.
“It was partly driven by a frustration that I kept coming across, particularly in policy, where the minute you talk about nature, people always put it into sort of a ‘fluffy bunny, pretty flower’ bucket. And they never see it as being a scientific relationship between health and nature, what’s going on in our bodies when we interact with nature.”
She wrote the book from a public policy perspective while also using her scientific knowledge.
Prior to joining the House of Lords, Kathy was working on several international projects, including the International Panel on Biodiversity and Ecosystem Services.
“We are doing a global assessment on nature and how it underpins so many functions that we all rely on. And my role, or one of my roles, was to find out the relationship between nature and human health.”
She kept coming across a 1984 study in the journal Science that determined that patients recovering from gallbladder surgeries had better outcomes and less pain when they were able to look out from their hospital windows at trees, rather than brick walls.
She says a big body of literature has been emerging in the last 15 to 20 years on the mechanisms of action in our bodies when we interact with nature.
When she worked at Kew Gardens, she realized that she was in a much better mood in the afternoon if she took her lunchtime walk in the gardens rather than down the street to shops.
These days, she keeps plants around her where she works. Her computer has a tree-themed screensaver. People can practice forest bathing, she says, but she also wonders, who has the time to lie in the forest for two hours?
“There are so many small tweaks you can make within your own lifestyle, your own daily interactions that can absolutely trigger these physiological and psychological changes in our bodies that really do bring about health benefits,” she says.
She notes that one experiment on psychological wellbeing showed that just 90 seconds of looking at trees on your computer screen, compared to looking at an urbanscape like the New York skyline, results in significantly lowering blood pressure.
Even a single white rose with green leaves on your desk, experiments have shown, lowers blood pressure.
A body of literature has been emerging in the last 15 to 20 years on the mechanisms of action in our bodies when we interact with nature, Kathy Willis says.
How Smells From Plants Affect Us
When you breathe a smell in, what you are smelling is a volatile organic compound, Kathy explains.
“It’s a carbon compound that when it hits air, it turns into a gas, evaporates, and that’s the smell you get. And when you breathe it in, it passes across the membrane in both your nose, but also in your lungs into your bloodstream.”
Researchers have measured people’s blood before they walk in a pine forest, and again after. They also measured the ambient air in a pine forest and found it’s high in pinene. “That’s the compound that creates that piney smell,” Kathy says.
After a 20-minute walk, there is a great spike of pinene in the blood.
Many compounds like pinene, once they are in the blood, interact with the same biochemical pathways as if taking prescription drugs, she says.
That’s why lavender makes you sleepier and sleep deeper, and why rosemary makes you feel more awake and alert. Their natural compounds change how we feel.
Other studies have shown that the compound cedrene, found in cedar and in hinoki oil derived from Japanese cypress, lowers adrenaline levels and raises “natural killer cells” — white blood cells that fight cancer — in the blood.
People who live in or near cedar forests have higher levels of natural killer cells, and people who walk through a cedar forest have higher levels for five days.
Limonene, found in citrus fruits, is shown to reduce inflammation in the esophagus.
The smells from plants enter our bloodstream, where the compounds can have positive health effects.
The Gut Microbiome
You’ve heard in recent years about the gut microbiome and how the microorganisms that live in your GI tract influence your health for better or worse.
One hypothesis that has gained support the more it has been tested is that spending time in nature will result in one’s gut microbiome adopting more good bacteria.
“In terms of our own gut microbiome, only 7% of it is inherited. 93% of it is due to our environment, which is why people are drinking probiotics and doing all these other things to try and change their gut,” Kathy points out.
“If you’ve got plants in your front garden, you will have this wonderful good bacteria being exuded from the plants. … If you spend time in that, your body adopts the signature of that microbiome.”
One double-blind study of kindergarten age children in Finland showed that children who played for a month in a sandpit full of soil trucked in from the local forest had much better gut flora than children who played in sterile sand. They also had a significant reduction in inflammation markers.
Cultivated soils are jam-packed with good bacteria.
“We should be gardening without our gloves on,” Kathy says. “We should not be putting chemicals on the soils that are going to kill all these wonderful bacteria.”
Working in soil influences the gut microbiome for the better.
Photo Courtesy of Kathy Willis
Gardening and Mental Health
A study carried out with the University of Copenhagen wanted to understand the efficacy of interacting with nature versus cognitive behavioral therapy, a therapy for depression.
“So they took a group of clinically ill people with mental health issues who’d been off work because of them for a year, and they split them in two,” Kathy explains.
One half did cognitive behavioral therapy with a trained therapist twice a week, and the other half went into the university’s gardens and joined in with gardening activities two times a week.
After the 10 weeks, they looked at how many people were back at work and how many visits they had with their doctor. They found similar results in both groups: 80% were back at work. But gardening is a much cheaper way to achieve the same result.
A year later they looked at who was still at work. Of those who gardened, 70% were still working, while only 60% of those who did cognitive behavioral therapy were still working.
Working in a garden is just as effective, if not more effective, than cognitive behavioral therapy, a study revealed.
Photo Courtesy of Kathy Willis
Overall Health
A meta-analysis of many studies that looked at heart attacks, strokes, mental health, etc. and the effect of gardening found that people who have an allotment (the name for a community garden plot in the United Kingdom) were the healthiest compared to people who only had a back garden or front garden.
“They concluded it was partly the diversity of different plants in the garden,” Kathy says. Also significant was the environmental microbiome
“Some people find a backyard stressful, especially if they’re by themselves. So therefore, you know, this is not always going to be brilliant to have your own green space. It’s better to go and walk in someone else’s.”
A few potted plants in the front garden can make a big difference, because people go out through their front door everyday and go into their backyard less.
Being around plants improves both mental and physical health.
Photo Courtesy of Kathy Willis
Houseplants Improve Environmental Microbiomes
Kathy is a big supporter of the spider plant.
“They did this lovely experiment where they shut this poor spider plant in a room, in a sterile room. And then they went back and measured the microbiome in the room. And this single plant had seeded the air, the ceiling, the walls, everything within eight weeks” with a good microbiome.
“A single little spider plant on your desk can make a huge difference,” she says.
But going outside is also hugely beneficial.
“I often now go and touch the plants, touch the leaves,” Kathy says. “I think that links you back to them, and you suddenly start to feel these different shapes and textures, and it brings the whole thing alive. You’re not just looking at — you’re feeling it, you’re touching it, you’re smelling it. Anyone can do that. And you can do that in two minutes, and you’ll absolutely get the benefits from it.”
Houseplants around where you live and where you work will not only bring cheer, they will improve the environmental microbiome in the space.
Photo Courtesy of Kathy Willis
If you haven’t listened to my conversation with Kathy Willis about “Good Nature,” you can do so now by scrolling to the top of the page and clicking the Play icon in the green bar under the page title.
How have gardening and being among nature improved your physical and mental health? Let us know in the comments below.
Links & Resources
Some product links in this guide are affiliate links. See full disclosure below.
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joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.
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Kathy Willis | Simon & Schuster
“Good Nature: The New Science of How Nature Improves Our Health” by Kathy Willis
“Botanicum” by Kathy Willis and Katie Scott
“The Evolution of Plants” by Kathy Willis and Jennifer McElwain
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Disclosure: As an Amazon Associate, I earn from qualifying purchases. I receive a commission every time you purchase a product through an Amazon affiliate link. Some product links in this guide are affiliate links. However, none of the prices of these resources have been increased to compensate us, and compensation is not an influencing factor on their inclusion here. The selection of all items featured in this post and podcast was based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Milorganite, Soil3, Territorial Seed Company, Cool Springs Press / Quarto Group and Dramm. These companies are either Brand Partners of joegardener.com and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship.
