Hands On Gardening - Japanese Knot Weed

Japanese knotweed is an invasive plant species that was planted extensively in the eastern United States and has spread to Wisconsin. It has rhizomes that can spread up to 65 feet underground and its roots can go at least nine feet deep.

Japanese knotweed is usually found in marshy areas, wetlands, and aside from people's gardens.

Japanese knotweed is a concern because it can produce viable seeds, which means they can germinate and sprout. This plant has the potential to clog waterways.

If you have a small patch of Japanese knotweed in your garden, you can pull it out manually by hand. Otherwise, cutting the plants halfway through the summer and spraying herbicide on them can be effective. It may need to be done a couple of times.

Japanese knotweed has reddish stems leading up to rounded leaves. If you see something in your garden with these characteristics, it's best to call the extension office to come out and identify it for you. It's important to get rid of it before it becomes established.