Wild parsnip (Pastinaca sativa) is biennial plant up to 4’ tall in the flowering stage. The plant spends one or more years in rosette stage (approximately 6” high), blooms under favorable conditions, and then dies. It has 5-15 egg shaped leaflets on both sides of a common stalk. It has flat-topped broad flower cluster 2 - 6" wide, numerous five-petaled yellow flowers and blooms from June to late summer.
Wild Parsnip is an aggressive weed with an extensive root system that makes it difficult to eradicate. Mowing plants when they are in bloom, and again one or more times that same summer when they re-bloom, can reduce the number of plants and may eventually eradicate an infestation. St. Louis County uses both methods (mowing in some locations, herbicide application in others) to control the spread of wild parsnip along roadways.
The herbicide (trade name “Escort”) will be selectively applied to wild parsnip patches by a professional applicator certified by the Minnesota Department of Agriculture. People and pets should not eat vegetation in sprayed areas, which will be marked by signs at the time of spraying, for at least two months. The chemical will be applied close to the plants in a manner that prevents it from getting carried towards homes in the air.
Contact with this plant can cause skin to become photosensitive; exposure to sunlight can cause severe blistering. The reaction has also been noted in animals ingesting this plant. Persons working with or near wild parsnip infestations, including cleaning mowers or other equipment, should wear appropriate protective equipment and clothing that covers all exposed skin.
Noxious and invasive exotic plants cause billions of dollars of economic losses every year for agriculture, natural resources management agencies and others. In addition, invasive plants are one of the main causes of extinction of native plants and animals because they crowd out native trees, shrubs and plants, reducing the diversity of native plants and habitat for wildlife. Costs are not billed to adjacent landowners.
Wild parsnip is spread by seed, which can be spread by animals, mowers, 4-wheelers, haying and hay bales, or other equipment.
Controlling invasive weeds like wild parsnip on your property can help stop the spread and negative impacts of invasive exotic plants. Unfortunately, wild parsnip can be particularly difficult to eradicate. Repeated mowing every summer to keep plants from setting seed will eventually kill it. Otherwise seeking professional help is likely the most effective option. The Minnesota Department of Natural Resources web site provides advice for controlling this and other invasive plants: http://www.dnr.state.mn.us/invasives/terrestrialplants/index.html.