The State of Michigan will, on occasion, place regulations on evasive plants. Sometimes, those regulations are extremely prohibitive. Japanese Knotweed is prohibited in Michigan. It is illegal to possess or introduce this species without a permit from the Michigan Department of Agriculture, and Rural Development.
Photo by MdE Creative Commons-Japanese Knotweed
It has been illegal to possess Japanese Knotweed in Michigan since 2005. It’s not illegal to have the plant on your property as it is understood that it is not there by your choice, but don’t mess with it. Call your local Dept of Agriculture and ask their advice as what to do. You might be asking what is so bad about a plant, that is actually quite edible, that the State would make picking it, moving it, digging it up, cutting it down etc, illegal? Well, simply put, it is a VERY destructive plant. Its root system will destroy pavement, asphalt, your building foundation and it crowds out any desirable native plants. In essence, it just does not belong here. It actually lives on the sides of volcanoes in Japan, getting covered by hot lava. It’s roots survive and push its way back up the cooled lava, even stronger than before. So why not poison it? It seems to love poisons. Anything you do; poison, dig up, cut down, burn down, harvest, look at it side ways, just makes this plant angry, making it come back with a vengeance. Some good news is, if you leave it alone, it might be content and not explode in growth. Efforts are being made to find ways of destroying Japanese Knotweed, but it still goes unchecked. The bottom line is, if you have Japanese Knotweed on your property, leave it alone and let your local Ag Department know its there. Even though it seems intrusive that the State would put such strenuous regulations on something as innocent as a plant on your own property, its actually for a very good reason. It’s to protect your property and the properties around you.