2026 Invasive Species Spraying

MANITOWOC COUNTY HIGHWAY DEPARTMENT 3500 State Highway 310 Manitowoc, WI 54220-9659 920-683-4345 RE: Invasive Species Spraying – Plant Growth Regulator As of May 4, 2026, our crews have begun applying treatments along county roads to help control and eradicate wild parsnip and other harmful invasive plant species. You may notice spraying activity continuing throughout the month of May. We are also applying a plant growth regulator to slow grass growth, which helps improve visibility for drivers. All applications are conducted by trained and certified staff using EPA-approved herbicides. These products are plant-specific and are designed not to harm birds, bees, butterflies, or other wildlife and beneficial insects in the right-of-way. As a result, grasses, milkweed, and other native plants can continue to thrive, supporting local wildlife and pollinators. Our crews plan to treat areas approximately 15–25 feet from the road shoulder along all county highways. Daily updates on spraying locations and progress will be posted on the Highway Department website. For more information, please visit our website. https://manitowoccountywi.gov/departments/highway/notices/