World’s tallest poison ivy plant found in Paris, Ont.

Robert Fedrock, dressed in a grey sweater and jeans, wrapping his arms around the base of the tree with the world's tallest recorded poison ivy vine travelling up the centre Photo by Amber Fedrock

A Paris, Ont., resident received a Guinness World Record last month after finding the world’s tallest poison ivy plant on their family farm.

Recorded at 20.75 metres tall, the poison ivy’s vines wind their way up a white ash tree in the forest behind Robert Fedrock’s farm. He says he initially found the plant hidden behind an overgrown bush of common buckthorn while making a trail years ago.

Fedrock only decided to submit the record to Guinness World Records, which didn’t have a category for tallest poison ivy plant at the time, in 2023 on a friend’s recommendation. This required him to clear the buckthorn from the area and inspect the rash-inducing plant up close. 

“I’ve gotten poison ivy rashes for less worthy occasions,” he says.

Fedrock was 100 per cent sure the plant was poison ivy—he’s spent just as much time at his farm as he has at his investment banking job—but Guinness World Records still needed him to have expert witnesses. 

“It wasn’t a ton of work, but it wasn’t a simple or quick thing either,” he says. He then contacted private botany consultant Corey Burt.

Poison ivy grows in two varieties in Canada, according to Burt. Most people recognize Toxicodendron rydbergii, the western poison ivy variation that grows in short bushes on the ground. Fedrock’s plant is instead a vine that scaled up a solid surface—the eastern Toxicodendron radicans variety.

Burt says the height of the record-holding plant isn’t unheard of, since the eastern variety grows an average of two to three metres tall, but easily passes 10 metres on larger trees. This kind of discovery raises awareness about poison ivy and its helpful impacts on the environment.

“Despite its bad rap—the rashes and blisters—it does provide food for a lot of native species,” he says. “White-tailed deer and songbirds will eat the fruits and the foliage, so the more information we have to understand this plant, the better.”

Both Burt and Fedrock think there are likely taller poison ivy vines in the world, but they agree this is the largest one that’s been recorded. Fedrock hopes opening this new category will encourage others to be more mindful of the plants around them: “Any attention that gets more eyes on plants is good.”

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