May’s Weed of the Month, wild parsnip (Pastinaca sativa), is a toxic plant with an edible root. Native to Eurasia, it escaped cultivation and is commonly found throughout Minnesota and North America.
Wild parsnip is a member of the carrot family. It produces a sap that can cause blistering, swelling, and discoloration of the skin when in the presence of sunlight. Protective clothing should be worn when working with this plant. Animals, including livestock, can also be burned by the sap in combination with sunlight.
Wild parsnip is a biennial that germinates from seed and spends one or more years as a rosette. Once it has enough resources stored, it sends up a flowering stalk, sets seed, and dies. It blooms from June to July, and the yellow flowers are large and flat-topped. Each leaf has multiple leaflets with saw-toothed edges. The plant forms a long, thick taproot that can make removal by hand pulling a challenge.
It is most commonly found in disturbed areas such as roadsides, trails, pastures, and gravel pits. Wild parsnip is highly invasive and can spread rapidly to replace native animal and plant habitat. It produces abundant seed which can stay viable in the soil for four years.
As a prohibited noxious weed on the control list, landowners must attempt to control the spread of wild parsnip seed. To manage wild parsnip, infestations need to be monitored and treated until the seedbanks are depleted.