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Poisonous parnsip presents persistent problems
Poisonous parnsip presents persistent problems
Wild Parsnip in full bloom photo from Wisconsin DNR Website


You may have noticed a boom in bright yellow plants along the roadsides and ditches in Richland County.
An abundance of rain and decreased mowing operations have led to a massive increase in Wild Parsnip, also known as poisonous parsnip.
Wild parsnip is native to Europe and Asia and has been eaten there since ancient times. It was popular for cultivation by the Romans for its edible root.
French colonists were thought to have introduced the plant to Canada and the British during the settlement of the original Thirteen Colonies-although it is not clear if it was accidental or on purpose.
 It was a popular root crop for consumption all the way until the mid-19th century, where the ubiquitous potato replaced it.
In a 1999 article written by David J. Eagen, a field botanist and naturalist who worked for the Institute for Environmental Studies at UW-Madison, for the Wisconsin Natural Resources Magazine, Eagen notes “Dried specimens at the University of Wisconsin-Madison herbarium date back to 1894 in southeast Wisconsin and a specimen was collected on Madeline Island at the northern tip of the state in 1896. Although not a native plant, wild parsnip has likely become ‘naturalized’ in all of Wisconsin’s 73 counties and is here to stay.”
The plant is identified most commonly by its bright yellow seed head, which can be seen for miles along the roadsides and in fields. But it also boasts rosette leaves that bear a strong resemblance to celery. The seeds of the wild parsnip are flat, round, yellowish and slightly ribbed and can remain viable in the soil for four years.
The leaves and stem of the plant contain a toxic sap which can cause painful trouble for those who encounter it.
There are some lucky people who aren’t allergic to it, but for most people the juices in the stem or the leaves can cause a large blister or blisters. It will typically start out like a brown spot and turn into a blister than can last up to a week.  Once the blister is healed, it will leave a scar that can last for six months up to two years. If it is small you may be able to let time take its course, but if the blisters are large or in sensitive areas like by your eyes, you should see a physician right away. Those who have fallen victim to the toxic sap should avoid popping their blisters as it may cause them to spread and lead to infection.  The burn like blister is also activated during the day, making warm sunny days when you may be out doing lawn work even riskier.
Wearing long sleeves, long pants, gloves and face protection can all help reduce your risk. Once inside, you should wash up with dish soap, since it is oil the plant secretes, dish soap will help remove that and lessen your chance for blisters.
Mowing before the plant goes to seed, pulling in early spring and spraying with herbicides are all considered viable methods to remove the vicious invasive.
The plant is a biennial, meaning it typically has a two summer growing season. In the first year the energy is used to establish a strong taproot. The easily recognized yellow seed heads we now see are the plant showing in its second season.
Humans are not the only ones at risk when it comes to wild parsnip.
Eagen notes “Animals can be burned in a similar manner to people if the animals have lightly-pigmented skin covered with little hair, so both plant juices and sunlight reach the skin.” 

Interestingly, wild parsnip is often confused with prairie parsley, a native prairie species that is listed as threatened in Wisconsin.  However, According to the Wisconsin DNR, Prairie Parsley is not currently found in Richland, Grant or Crawford counties.