Yes, Japanese Knotweed can potentially be spread on shoes. If small fragments of the plant’s rhizomes or stems get stuck in mud or soil on your shoes, they can be transported to new locations. Since even tiny pieces of rhizome, as little as 0.7 grams, can grow into a new plant, walking through an area with knotweed and then tracking soil elsewhere can cause the plant to establish in a new spot. To prevent this, it’s important to thoroughly clean shoes after being in areas known to have Japanese knotweed, particularly if you’ve been in disturbed soil.