You may have both curled dock and broad leaf dock. Occasionally on older farm sites there's rhubard still growing in a clump. Dock spreads around here and there singluarly.
Look up Ontario's invasive weeds list.
http://www.omafra.gov.on.ca/english/crops/facts/ontweeds/curled_dock.htm
We are situated on an old farm and there are both docks and a couple of clumps of rhubarb. The rhubarb leaves are huge with curled edges and almost ready to cut now. The taste test is may help.
Yesterday we had to do the taste test with a cute white flowered wildflower. Looked it up and decided it was the invasive wild garlic.

Then it's most likely dock. Shoot! I was really hoping for some rhubarb!