Spread of poisonous wild parsnip linked to urban sprawl: gardening expert

The wild parsnip is pictured.

The spread of wild parsnip, a poisonous and invasive plant, can be linked to increasing urban sprawl, according to one gardening expert.

Recently, an 11-year-old boy from Pickering, Ont., was left with a bad scar on his leg after coming into contact with the plant.

Mark Cullen, Canada AM's gardening expert, said the spread of the plant is happening as humans increasingly move into what was previously farmland.

"We're basically taking farmland and turning it into urban space," he told CTV's Canada AM. "And then we're turning some of that urban space into greenspace."

In those areas where residents are allowing the greenspace to "naturalize," noxious plants including the wild parsnip are spreading, Cullen said.

The wild parsnip has been in Canada for more than 400 years, and is part of the carrot family. It can be found across Canada, where it thrives during the warmer months.

The plant is identifiable by its yellow "umbrella-like" flowers, which closely resemble the flowers of Queen Anne’s Lace.

While the root of the plant is edible, it is the sap in its stem that can cause health problems.

If you get the sap on your skin, and your skin is then exposed to the sun, you can break out in a rash and develop blisters and burns. In extreme cases, you can even go blind, if the sap gets in your eyes.

Cullen said concerns over the plant shouldn't prevent Canadians from heading outside. He noted that many popular plants have poisonous parts, including tomato and rhubarb plants. What's important, he said, is to be educated.

"Get out there, enjoy the outdoors, but do it knowing," Cullen said.

This sentiment was echoed by Deborah Metsger, a botanist at the Royal Ontario Museum.

"We need not be frightened of plants if we take the right precautions," she told CTV Toronto.

Hikers can protect themselves against the wild parsnip and other poisonous plants, by wearing long pants and sleeves while on the hiking trails.

If you have small clusters of wild parsnip on your property (fewer than 100 plants), you may be able to manage the removal of the plant yourself. However, if you have a larger infestation, it is recommended that you contact a professional exterminator.

Get tips on how to manage and remove the plant by visiting the Invading Species website.

With files from CTV Toronto's Pauline Chan