Use of architectural fungi exhibits a greener side to the RHS Chelsea Flower Show

Historically, show gardens at the Chelsea Flower Show couple artful, high-end planting design with similarly ambitious architectural structures, from walls and waterways to shelters, bridges and pavilions. However, with the Royal Horticultural Society (RHS) striving towards greener credentials for its signature and world-renowned annual flower show – including reductions in carbon emissions and waste materials, and ensuring its short-lived exhibition gardens are relocated to lasting homes, post-show – more sustainable approaches to such hardscaping elements are integral to its future. Fresh this year (if ‘fresh’ is the word) is the ingenious use of architectural fungal material, with organic, ’root-like’ fungal mycelium strands providing the cladding for a pavilion within one of 2025’s standout Chelsea gardens.

For his gold medal-winning ‘Avanade Intelligent’ show garden this year – undoubtedly a centre of interest along the show’s prestigious Main Avenue – garden designer Tom Massey has collaborated with architect Je Ahn of Studio Weave (whose portfolio includes the striking Seosaeng House in South Korea and a transformed Devon cottage, Made of Sand) to conceive a low-carbon garden of predominately reused materials. Highlighting the vital importance of urban trees (in filtering air pollution, cooling streets and supporting wildlife), Massey and Ahn’s garden features attractive, architectural species of Chinese cedar and Sichuan pepper trees, but also a wooden pavilion with outer panels fabricated from mycelium-bonded wood shavings. ‘Part of the brief we set ourselves was to make the whole landscape from reused and low-carbon materials’, says Ahn. ‘Talking with Avanade [the garden’s sponsor], we decided we’d like to grow certain elements of the building itself, and mycelium was the perfect material’.

Explaining the fungal fabrication process, Chelsea gold-medalist Massey describes how waste pulp wood – including wood shavings resulting from the pavilion’s construction – was inoculated with mycelium, which grew and bonded the wood together like glue, creating the organically patterned panels. ‘The mycelium stops growing when you air-dry it, and fixes in place. It will slowly degrade over time and can be composted and replaced, offering a carbon-negative, nature-based material solution.’ Unlike plastic and composite materials, he says, this is a material that doesn’t outlive its useful life. ‘There’s nothing toxic in it – you just compost it, and it gives back to the soil.’

Massey and Ahn’s Chelsea garden also draws attention to the perils faced by trees planted in urban environments. ‘Around the world urban trees are under threat’, says Massey. ‘Three in ten die within the first year of planting, 50 per cent die within ten years. That’s because of a range of factors, including climate change.’ To combat this, the garden demonstrates innovative use of AI to monitor the health of its trees, with sensors recording elements such as growth, sap flow, air quality and soil conditions. The AI then analyses this data to provide nurturing advice. 'The AI has been trained with specific information on each tree – how it should be grown and its water requirements. It also accesses weather data, so it can say what you do and don’t need to keep an eye on. It gives gardeners insights into what’s going on, so they can devote resources to a particular tree.’

The Avanade Intelligent Garden, which also features layers of biodiverse and naturally resilient woodland plantings, including a range of edible species, will be permanently relocated to Manchester's Mayfield Park following its exhibition at the Chelsea Flower Show this week.

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