Thank you for your question!

This does look like Japanese knotweed, unfortunately. It’s one of the more aggressive invasive plants we deal with in Minnesota, and it spreads rapidly through a large underground rhizome system. That’s what makes it so tough to eliminate once it’s established. It’s also on the state’s noxious weed list, which means it should be controlled to prevent spread.

The University of Minnesota Extension has a really helpful guide with photos and details here: https://extension.umn.edu/identify-invasive-species/japanese-knotweed

From a gardener’s standpoint, this is all about persistence and layering your approach. The Minnesota Department of Agriculture (see PDF attachment) recommends a few control methods, especially at this early growth stage when it’s just emerging from the root crown:

- Repeated digging to remove rhizomes

- Smothering (like covering with a tarp)

- Grazing (though not practical for a home garden)

I’d start by digging out as much of the root system as you can. Go deep and be thorough, but expect that you won’t get it all the first time. After that, cover the area with a heavy, dark tarp to block light and suppress regrowth. Then stay on it. Check the area regularly and remove any new shoots right away.

This will likely take multiple rounds this season and into next year, but staying consistent early on gives you the best chance of getting it under control.

Hope this helps!

-Victoria

University of Minnesota Extension Master Gardener