Wild parsnip grows abundantly along many of the ditches and also around the storm water pond which I like to visit. In the photo it is the plant with the umbrella like head with yellow flowers. It came to Canada with European settlers as a food plant for its starchy root. While the root is edible the stems of the plant contain a sap that can cause blisters, rash, and intense burns when exposed to the sun. Most of us know better than to meddle with it.
It is an invasive species spreading readily and very difficult to eradicate. It can take years to completely kill off all the wild parsnip. Herbicides are strictly controlled here with some of the nastier ones banned altogether.