Imagining the Mossy Cities of the Future

This story has been co-published by  Reasons to be Cheerful  and the  Outrider Foundation . I n 2012, Philip Wallisfurth wanted to save a tree. Citizens in Aachen, Germany, were protesting plans for a shopping center that threatened a 150-year-old tree. Wallisfurth , then an aspiring street artist, wondered if he could use moss — instead of his usual spray can — to support the campaign. He harvested moss from a local park, used yogurt as an adhesive and stuck two-meter-high letters onto the construction fence, spelling out “greener living.”  The reactions surprised him. “People loved it,” he recalls. “Many took pictures and some spontaneously hung flowers in small vases onto the fence.” He had stumbled upon a medium that was soft, tactile and alive — and a natural way of occupying public space. YouTube tutorials suggested mixing moss with buttermilk in a blender, but the results disappointed him. Through trial and error with different mosses and yogurts, he developed his own approach to making “bio-graffiti.”  Artist Philip Wallisfurth developed his own approach to making “bio-graffiti with moss.” Courtesy of Philip Wallisfurth Two years later, whiskey maker Jack Daniel’s hired him for a campaign. In Cologne, Wallisfurth covered an eight-by-eight-meter wall with moss lettering, spelling out a motto he lives by:   never give up trying to do what you really want to be happy Now an artist with international projects and a studio in Berlin, Wallisfurth, 42, mostly paints large, colorful murals and designs anamorphic installations, room-filling works that seem to change shape depending on the viewer’s perspective.  But moss continues to appeal to him for several reasons. He feels it’s uniquely suited to transform uninspiring urban spaces into places that feel more welcoming — and it has environmental benefits, too. He learned from speaking with scientists that moss can convert carbon monoxide and nitrogen dioxide into oxygen. “It also acts as a natural air filter and absorbs noise,” he notes. Moss continues to appeal to Wallisfurth for its ability to make spaces more welcoming and its environmental benefits. Courtesy of Philip Wallisfurth There are more than 13,000 recognized species of moss. The unassuming plant that most homeowners would like to scrape off their driveways offers more than unusual shades of green. It can retain moisture, dampen sound and, under the right conditions, help regulate the temperature of the surfaces it covers. Wallisfurth dreams of turning entire structures — for instance, train stations — into buildings where moss improves the air and atmosphere.  As cities grapple with increasingly dangerous heat, Wallisfurth’s artistic experiments intersect with a serious question for architects and climate researchers: While concrete, asphalt and masonry store the sun’s energy, cities are searching for ways to keep buildings and public spaces cooler. Could this small, overlooked plant become part of the answer? Weighed down by negative news? Enter your email below to receive our smart, uplifting newsletters. Or click here to choose exactly which ones you want [contact-form-7] Moss is remarkably adaptable. It has no conventional root system but absorbs moisture directly through its surface and can tolerate long periods of dehydration. A 2026 field study in Seoul showed moss-based green roofs reduced peak roof-surface temperatures by about 19° Celsius and maximum indoor temperatures by 2 to 3.5° Celsius during heat waves, while a 2026 peer-reviewed study from TU Delft in the Netherlands found that hydrated moss can produce evaporative cooling and insulate underlying surfaces.  Credit: Lukas Gojda / Shutterstock Moss is remarkably adaptable. It has no conventional root system but absorbs moisture directly through its surface and can tolerate long periods of dehydration. It can retain moisture, dampen sound and, under the right conditions, help regulate the temperature of the surfaces it covers. As promising as these findings are, the reality is more complex than a green coating that simply cools whatever it covers. According to the Dutch researchers, the cooling effect only lasts as long as the moss is hydrated. Crucially, they found that dry moss exposed to direct sun can actually become warmer than bare mortar. So the question changes: Can cities engineer walls and roofs with moss that stays moist when cities most need cooling? Several startups are betting that the solution lies in redesigning the surfaces themselves. In London, Alive Labs produces moss-covered panels to turn city walls into living infrastructure. Founder and architect Nicky Naidu wants to change how the construction industry thinks about moss, which is often treated as a sign of neglect. “Moss gets a bad rep. But moss has intrinsic beauty, and we want to bring that beauty to cities,” Naidu told Reuters . “It’s carbon negative, bioreceptive, cost-effective and fire-safe. Everything that the industry needs and requires.” The company’s panels are made of a base material Naidu describes as bioreceptive concrete designed to support the growth of moss. The living wall systems incorporate controlled irrigation, delivering moisture directly rather than relying on rainfall or conventional surface spraying. Naidu argues that the moss walls are easier to maintain than conventional green walls because moss needs no soil to flourish.  Alive Labs produces moss-covered panels to turn city walls into living infrastructure. Courtesy of Alive Labs In the Netherlands, Respyre has developed a similar concept with “Mosscrete,” a bioreceptive concrete that can be seeded with moss and also features an “ integrated, automated irrigation system that keeps the moss sufficiently hydrated, particularly during warmer and drier periods .” Both companies have moved from the prototype stage to making their panels commercially available. In Berlin, Green City Solutions built the world’s first vertical moss farm on 1,200 square meters to grow moss for sustainable air filters.  The next step for the industry is to measure results in real life under varying temperatures and conditions, to determine where moss performs well enough to justify the investment. Not every experiment requires new materials or elaborate infrastructure. In Santiago de Compostela, Spain, a chance observation during the pandemic led city officials and university researchers to reconsider the vegetation growing between the city’s paving stones, including moss. After thermal cameras showed that stone surfaces with these small patches of greenery measured up to 25° Celsius cooler than bare paving, the city opted to leave the “urban microgreen” in place as a low-cost way to mitigate heat.  A Respyre test panel after irrigation. Courtesy of Respyre Philip Wallisfurth keeps experimenting with the greenery, too. For a temporary installation, he transformed an entire living room in Berlin into an otherworldly moss-covered landscape. Again, he noticed people’s positive reaction. “The smell simply calmed people down,” he observed. “If you had a living moss wall in an office that was regularly watered, it would create an incredibly pleasant working climate. Plus, it filters the air and absorbs noise — it’s actually dreamlike.” Wallisfurth learned that most conventional moss art one finds in rooms is made from moss that has been dried and preserved with chemicals, eliminating the need to water it but also killing most of its environmental benefits. “It’s dead,” he says.  His own bio-art has limits. Without preservation, the moss typically dries and dies within three to six months, depending on the surrounding dryness and acidity. “Like street art,” Wallisfurth notes, “it’s impermanent, too.” The walls of a bank building in Utrecht before and after renovation with Respyre’s bioreceptive concrete. Courtesy of Respyre But learning more about moss also made him reconsider where his material comes from. His sister, a nature guide, calls moss the “lungs of the forest” and told him it was wrong to take moss from forests and public spaces. He now sources his moss from an abandoned army training ground that is likely to soon be a construction site. His desire to create sustainable moss installations sometimes clashes with his clients’ expectations. Several big corporations approached him about creating moss pieces, he says, only to dismiss his concerns about sustainable sourcing. “They told me: ‘We don’t care. It just needs to look green in the pictures.’” He shakes his head. “That was a downer. It showed that most people only look at it as a means to an end.” The exchange captures a broader risk in the rush to make cities greener: The living material can become a visual shorthand for sustainability, even when its environmental value has not been proven. It might look green but actually be greenwashing. Credit: CinemaPhoto / Shutterstock “If you had a living moss wall in an office that was regularly watered, it would create an incredibly pleasant working climate. Plus, it filters the air and absorbs noise — it’s actually dreamlike.” –Philip Wallisfurth In addition to making his own moss art, Wallisfurth enjoys running moss workshops for kids at schools. Children love to experiment with the soft, tactile material, he says.  Growing up in a rural part of the Eifel in Germany, he remembers walking barefoot across moss, and nature was his refuge when his own childhood was marked by loss. His parents died of cancer when he was young, and his brother was killed when Wallisfurth was only 14. He trained as a foreign-language correspondent and hotel manager before moving to Berlin and pursuing art. He turned to art explicitly as a means to brighten places up and turn rooms into positive spaces. “That’s what drives me,” he says. “Positivity is simply a much better way to deal with things. Of course, not everything is positive, but I have to try to stay positive.” His favorite projects begin with dark, inhospitable places and turn them into areas where people like to spend time. “That’s my goal as an artist.” Wait, you're not a member yet? Join the Reasons to be Cheerful community by supporting our nonprofit publication and giving what you can. Join Cancel anytime He believes he wouldn’t be an artist without his biography. And he sees a similar resilience in the plants: “A specialist once told me I could put moss in the oven at 270° Celsius, and if I water it afterward, it will come back to life.” In that way, he says, “Maybe I’m a little like moss. You can destroy it, but it simply grows again. It’s a fighter.” The post Imagining the Mossy Cities of the Future appeared first on Reasons to be Cheerful .