An artist dishes up Dublin’s invasive species

Walking through Ranelagh Gardens last Monday, artist Luke Casserly says he notices the seagulls, the pigeons, the big trees. 

Sure pigeons are everywhere but he likes them, he said. He likes this park too.

It’s not a big park, there’s an oval pathway looping a small lake with ducks and a centrepiece of green brush full of inaccessible ripe blackberries. 

He wasn’t expecting to see any Japanese knotweed there – and he didn’t. Dublin City Council has spent heavily trying to eradicate the plant.

Casserly has been thinking this past year about knotweed and other invasive plants, as one of Dublin City Council’s biodiversity artists in residence. His work isn’t about endorsing the species, he said, but about reframing how we think about them.

“I was really intrigued by this universal loathing of a species,” he said. “When we talk about ‘invasive’ and ‘non-native’ as inherently negative things, that’s sort of colonial language. The ecosystem is kind of … it’s everything.”

Knotweed, for example, can grow on volcanic ash and recent lava flows. It was imported from Japan to Europe in the mid-1800s and first reported in the wild in Ireland in 1902. 

The problem is really that it’s too good at what it does, said Casserly. “It spreads so quickly. But it’s not the plant’s fault. Humans brought it here.”

Pesky nature

As part of his residency, Casserly began making kombucha with Japanese knotweed from his own garden, carefully harvested, he stressed, since even tiny fragments of the plant can spread it. 

Japanese knotweed is part of the same botanical family as rhubarb and tastes similar – only more sour, he said. “You can make crumble, jam, chutneys,” he said.

That experiment became the seed for a new cookbook, Pesky Nature, a collaboration by artists and ecologists reimagining the role of invasive species in Dublin.

Illustrator Fergal Styles, a longtime friend and collaborator of Casserly, did sketches of the plants for the book. 

“The idea was to make them look like field notes – quick, throwaway, casual, like something done on-site,” says Styles. “It just seemed to fit the roughness of these plants.”

Casserly’s former lecturer at the National College of Art and Design (NCAD), artist Gareth Kennedy, contributed a recipe containing three-cornered leek leaves and wild garlic leaves.

And other collaborators added their own takes, including chef Christopher Mullen, who used potatoes – a reminder that Ireland’s most iconic crop is from South America.

“It raises the question: when does a non-native plant become local?” said Casserly.

Beyond control

Mary Tubridy, an ecologist and biodiversity planner, said she loves the idea of Pesky Nature. 

The issue with invasive species is, you can’t control them, Tubridy says. Encouraging people to harvest them is a way to take back power.

The problem with invasive plants is, she said, that humans introduced them, not wind, sea, or natural spread, and they can overwhelm native ecosystems. 

Eradication of Japanese knotweed for example,  is laborious and expensive: a cycle of cutting and spraying over years, careful disposal, cleaning boots and machinery to avoid spread.

“They don’t just happen here,” Tubridy said. “Humans brought them, often because they were pretty, not realising how prolific they could be.”

Japanese knotweed, for example, was imported to Europe by Phillipe von Siebold, according to a 2000 paper by biologists from the University of Leicester detailing its history, titled “From Prizewinners to Pariahs”.

It “was awarded a gold medal in 1847 by the Society of Agriculture & Horticulture at Utrecht for the most interesting new ornamental plant of the year”, according to the catalogue of von Siebold’s company. 

But Tubridy agreed that Casserly’s approach opens up space to think differently. 

“Of the millions of species in the world, humans only eat a few hundred. There’s huge scope for exploiting others,” she said. “And if we exploit invasive species that we consider undesirable, that’s even better.”

Japanese knotweed’s potential as a food was among the virtues Von Siebold extolled in his catalogue when trying to sell it back in the 19th century, according to the University of Leicester paper. 

“An accompanying seven line foot-note in this price-list extols its great vigour, its combination of ornamental and medicinal use, its value in protecting young plantations from wind and sun, its edible young stems and leaves and a rhizome highly valued in Japanese and Chinese medicine,” it says.

Beyond eradication

For Casserly, the project is as much about empathy and language as it is about food. “It’s certainly not an advertisement for planting more non-natives,” he said. “But since they are here, what’s our relationship with them?”

During his residency, he invited council staff to join him on nature walks. At first he called them biodiversity walks, but he noticed people found that word alienating. “Time and time again, Japanese knotweed came up,” he said. “It was seen as the ultimate villain.”

He wondered if, instead of only trying to destroy these plants, we might also learn from them: their resilience, their adaptability, their persistence in hostile conditions.

For him, making Japanese knotweed kombucha became a metaphor. Kombucha itself is a living culture – a symbiotic community of yeast and bacteria – that thrives through interdependence and care. 

“It became a useful tool to open conversations,” he said. “We respond more deeply through sensory things, rather than talking.”

The resulting cookbook, Pesky Nature, will be shared first within Dublin City Council, before being made more widely available, but the details on this are yet to be confirmed, Casserly said.

“It’s not activism” he said. “But art can explore these things laterally, and maybe offer us more empathetic ways of seeing what we’d otherwise just call pests.”

Funded by the Local Democracy Reporting Scheme.