Wild Parsnip Continues to Spread in Wisconsin

Monday, July 11th, 2022 -- 8:01 AM

Wild Parsnip, Pastinaca sativa, is an invasive member of the carrot family that continues to spread into unmanaged areas throughout Wisconsin.

It likes to grow in sunny, grassy areas along roadsides, railroads, and field borders but is not limited to these conditions. Primary means of spread is by seed that can be moved long distances while mowing roadsides after the plant sets seed.

The biggest concern isn’t the fact that it is invasive and rapidly spreading but that it will cause burns and blistering of the skin if you come in contact with plant sap in the presence of sunlight. This is known as phytophotodermatitis.

Blisters and rashes appear 24 to 48 hours after exposure. Blisters do not spread like poison ivy but are uncomfortable and may leave scars lasting for several months to two years.

Early detection when populations are small allow for pulling or digging.  Be sure to wear gloves, long sleeves, long pants, and safety glasses or face shields to avoid skin contact with the sap.

One can simply cut the taproot with a shovel or spade 1 – 2” below the soil surface. With larger populations mowing is an option if done after emergence of flower heads, but before seeds enlarge.  Additionally, several chemical options exist.

Be sure to read and follow label directions when using chemicals.  For more detailed management options see the University of Wisconsin-Madison Extension wild parsnip management publication A3924-15 at the Learning Store website https://learningstore.extension.wisc.edu/.

Feel free to contact us with questions and/or comments.