Editor’s Note: Call to Earth is a CNN editorial series committed to reporting on the environmental challenges facing our planet, together with the solutions. Rolex’s Perpetual Planet Initiative has partnered with CNN to drive awareness and education around key sustainability issues and to inspire positive action.
London
CNN
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For the first time in history, the majority of humans live in cities — spaces often defined by concrete, glass and a disconnect from the natural world. Access to nature is no longer guaranteed.
London-based environmental activist Ellen Miles, 31, is trying to change that. “Before we urbanized the world, everyone had access to nature all the time.” Miles tells CNN. “Now, nature is becoming an afterthought.”
In 2020, Miles founded Nature Is a Human Right, a campaign advocating for daily access to green spaces to be recognized in the Universal Declaration of Human Rights. Frustrated by the slow pace of institutional change, Miles says she “lost faith in the top-down process.” So she took matters into her own hands. Her weapon? Not protest banners or petitions, but seeds and shovels.
She became a so-called guerrilla gardener — “Grassroots planting in a public place, with a purpose,” Miles explains. “Think of it like graffiti, but with wildflowers instead of spray paint.” This form of urban activism involves transforming neglected or overlooked spaces — cracks in pavements, roadside verges, abandoned lots — into mini-oases for people, pollinators and biodiversity.
What began during the Covid pandemic — when parks were shut and access to green space became scarce — grew into a weekly ritual. Miles and her neighbors would meet on Sunday mornings, armed with bulbs and trowels, planting in overlooked corners of the London Borough of Hackney.
In the UK, guerrilla gardening occupies a legal gray area: while planting on public land without permission is not technically lawful, authorities often turn a blind eye — so long as it doesn’t cause damage, obstruction or a public nuisance.
According to the Royal Horticultural Society, guerrilla gardeners should ensure their planting doesn’t inconvenience others and be careful to not restrict public access or create trip hazards. It’s also important that anything planted is removable, and that the roots won’t cause structural damage to sidewalks and buildings.
Guerrilla gardening dates back to the 1970s, when the Green Guerrillas, founded by Liz Christy in the US, transformed vacant lots into community gardens. The movement has since spread worldwide, from Ron Finley, the “Gangsta Gardener” in Los Angeles, to Ta Mère Nature in France, and the Ujamaa Guerrilla Gardening Collective in South Africa.
Miles has brought the underground movement into the spotlight on TikTok and other social media. Her upbeat videos demystify the process, showing everything from creating seed bombs to planting moss graffiti — a form of street art where living moss is used to create patterns or words on walls. “I wasn’t a gardener. I was learning as I went along,” she admits. “But I just wanted the streets to be greener.”
As Miles’ seeds grew, so did her online following. “Young people today are very awake to issues like climate change, inequality, and mental health,” Miles says. “Guerrilla gardening intersects with all of that. It’s something you can do with your own two hands and see the impact immediately.”
“A lot of activism can feel intangible,” she adds. “With guerrilla gardening, you see the results. It’s empowering.”
And it’s more than just symbolic: “It’s been shown that having access to green spaces is as vital to your mental and physical health as regular exercise and a healthy diet,” says Miles. “We need it around us. We need the phytoncides (compounds plants release into the air) that plants produce. The experience of having plants around us calms us.”
A study of 20,000 participants by the UK’s University of Exeter found that people who spent at least 120 minutes a week in green spaces reported significantly better physical health and psychological well-being than those who didn’t. For young children, access to green spaces has been linked to reduced hyperactivity and improved attention spans. Communities can benefit too: a US study showed that greening vacant lots can lead to lower crime rates.
Miles’ message is simple: anyone can get involved. “It’s spring now,” she continues. “Find native wildflowers, scatter them when it’s raining then you won’t even have to water them.” For those who want to go further, Miles has written a book on the subject and teaches a free four-week online course through the nonprofit Earthed, which has attracted over 300 participants. She advises gardening as a group — community is key.
Her vision is bold but refreshingly practical: “Why aren’t all our sidewalks lined with hedges?” says Miles. “Our buildings could be covered in plants. Our rooftops and bus stops could be buzzing with flowers. It’s a no-brainer.”
