Parsnip is great in soups or part of a roasted vegetable medley, but if you see it growing in a ditch it’s best to steer clear.
Those volunteer plants are likely wild parsnip and they’re poisonous to the touch, explains Ontario Ministry of Agriculture, Food and Rural Affairs weed specialist Mike Cowbrough. The poisonous weed has gained a strong foothold in eastern Ontario and more patches are now showing up in the western portion of the province, and across Canada.
In this video, Cowbrough offers tips on how to identify, handle and control the pest. Visually, the yellow plant has dill-like features with flowers in an umbrella-shaped seedpod. It stands between one and one and a half metres. The stem is hairless and each leaf has four to five sections of leaves.
When the plant is broken it contains sap that can cause dermatitis or blistering on human skin.
Cowborough says farmers and other landowners can easily control patches of two or three plants by digging them out with a shovel while wearing protective gloves. Mowing the plants has proven ineffective. To control bigger patches, landowners will need to use herbicides.
“If you are going to use an over-the-counter product to control wild parsnip, Roundup is the most effective,” says Cowbrough. Simply follow the instructions and apply the herbicide to the leaves of actively growing plants.
The best option is selective herbicides. Cowbrough notes there are two selective products – Truvist and Clearview – that have been registered for eastern Canada. These control the wild parsnip but leave desirable vegetation and grasses to stabilize the soil and compete with new seeds when they germinate. “That’s our strategy when we get into big patches of wild parsnip on municipal and rural land,” explains Cowbrough.