FLORENCE, Wis. - The UW Extension office in Florence County is encouraging residents to take steps to control wild parsnip, an invasive plant that can cause rash and blisters in humans.
Scott Reuss of the UW Extension said that the plant is currently in bloom.
Wild parsnip has an upside down, umbrella-shaped flower head with yellow flowers, and is found in a variety of soil types. Generally, the plant thrives where the water availability is fairly good.
There are many other plants in the parsnip family that are also in bloom right now, but wild parsnip is the only one with yellow flowers.
Wild parsnip has negative environmental characteristics, such as having the ability to crowd out some native wildflowers, but it is actually more problematic to humans than to the environment.
This plant contains a chemical that causes a severe rash and blistering when exposed to skin and sunlight.
The rash can last for many days and may cause permanent scarring. The blisters may also lead to infections, especially in children.
Control centers on preventing seed set. Physical control via mowing or pulling will successfully prevent seed set and effectively kill the plant.
Wild parsnip is a biennial that ends its life cycle with flowering and seed production. First-year plants will only have leaves coming out of a central crown, just like a carrot.
When working with or around wild parsnip, be sure to wear long pants, long sleeves, and gloves to prevent exposure to the plant sap.
Chemical control is also an option if mowing or cutting is not viable.
The best time to control patches is actually later in the
fall, or early next spring, as this will control the young plants that will flower next year.
Spraying during, or just after, flowering is not very effective, as the dying plants can still produce viable seed.
Glyphosate spot-spraying of individual plants or small patches is effective, but removes all other plants, as well.
A three-way herbicide product containing 2,4-D, dicamba, and mecoprop will usually control it without killing grasses in the area.
For more information about the wild parsnip or any other horticulture issue, contact Reuss or Deb Simons at the Florence County UW Extension office at (715) 732-7510 or toll free at 1-877-884-4408.
Instead of bringing plant samples to the office for verification, please e-mail digital photos to scott.reuss@ces.uwex.edu.
More information on various invasive plants and other horticultural pests is available on the Marinette County UWEX webpage at www.uwex.edu/ces/cty/marinette.