This field of yellow flowers near O’Reilly’s Bridge, a popular fishing spot, is poison parsnip. BRIAN GREEN

Pretty to see but dangerous to touch, wild weed is thriving

Add “poison parsnip” to the list of miseries being visited upon Pelham in this year of the pandemic. A relative of Giant Hogweed, the wild parsnip can produce blistered skin and a burning rash, even cause blindness if it gets near the eyes. Chemicals in the sap react with UV rays in sunlight to burn the skin, a reaction that can take years to fully disappear.

Fay Suthons lives on the Wainfleet side of the Welland River and has been combatting the invasive plant for more than five years, and has observed its spread on the Pelham side of the river near O’Reilly’s Bridge, a popular spot for people to launch boats and fish. She has seen people walking through the parsnip and even collecting the flowers in vases to take home.

The plant looks similar to Queen Anne’s Lace, except that parsnip blooms are yellow rather than white. BRIAN GREEN

On her property, she enlisted the help of Kayanase Greenhouses from the Six Nations, thinking that Indigenous horticulturalists would have the best knowledge of how to eradicate the plant. After three years of targeted spraying, the foreman from Kayanase advised her to give up trying to control the spread and concentrate on the immediate vicinity of her yard. Seed spread from the Pelham side would make all attempts at control doomed to fail, he said.

Jason Marr, Pelham’s Director of Public Works, says that the Town receives “a handful of resident concerns about a number of noxious weeds including wild parsnip, hog weed, poison oak and poison ivy, annually,” and employs a licensed contractor to deal with the problem using herbicide. While this year the Town has received notification about poison ivy and hogweed in rural roadside locations, they have not treated wild parsnip. Neither the NPCA nor the MNRF has a mandate to control noxious species except on land that they directly control, but the non-profit Invasive Species Centre compiles sightings of invasive plants and assists in control measures.

Wild or poison parsnip resembles Queen Anne’s Lace, but instead of white flower clusters in a parasol shape, its flowers are yellow. Typically growing about .5 to 1.5 metres tall, it has deeply grooved green stems and leaves with sawtoothed leaflets arranged in pairs opposite each other along the stem. According to the Ontario Invasive Plants website, “Wild Parsnip is most often found in disturbed areas (i.e. railway embankments, roadsides, trails, shorelines, ditches, beaches, forest clearings and areas such as abandoned mine sites, quarries, and waste areas).” The plant was introduced from Europe in the 19th century and by the 1940s it was reported in every province.

As Fay Suthons found out, it is very difficult to eradicate, requiring diligent and frequent control. It can be (very carefully) dug up and left to dry out or mowed, but both treatments need to be repeated for several seasons, and mowing during the summer can serve to spread the seeds, making the problem worse. Covering the plants with a black plastic tarp will smother them if it is left in place for a season, but once it is removed, care must be taken to ensure the plants don’t grow back.

If you are exposed to the sap of the wild parsnip, stay out of the sun until you can wash thoroughly with soap and water and keep the affected area covered. If burns or blisters develop, seek medical attention.