noxious weed

To find county-specific noxious weed information, search for your county's name along with terms like "noxious weed" or "weed management plan" to find local resources, lists, and control information, as seen for Larimer County, CO and Klickitat County, WA. State governments often establish the lists and laws, with counties responsible for implementing management plans and enforcing them on unincorporated lands. 

In our county, https://tualatinswcd.org/species/purple-loosestrife/ this pretty flower is on the list.