If you use the beautiful Southwest bike path in Madison you may have seen this sign letting us know that Japanese knotweed is in the area. City Engineering staff are engaged in a multi-year process to eradicate this invasive plant.
The weed is incredibly hardy and can actually grow through, and destroy concrete infrastructure, and lead to erosion and flooding. Among other things, it threatens wetlands.
As you can see from this link effective treatment involves a multi-pronged approach including cutting and herbicide application. The plant not only grows very tall, cutting sunlight out to small plants, but also includes below ground rhizomes. I absolutely support City efforts to treat this invasive, and suspect we will be hearing more about their efforts.