Iowans are being warned about large patches of wild parsnip growing right now across the state.The weed can be found in road ditches, fields, along bike trails and in prairie areas. Many people don't realize they are coming in contact with it until burns, blisters, and welts later develop.Also known as poison parsnip, the plant looks like a dill plant or Queen Anne's lace. It is yellow and grows about four feet tall.Some people report the reaction after mowing throw a patch of the parsnip.The damage it causes can hurt for weeks and scars can stay with you for years. Chemicals in the juice of the poison parsnip react with sunlight and cause a breakdown of cells and tissues.Wild parsnip is spreading across Iowa in road ditches. In a short amount of time, it can take over an area and crowd out the native plants.