Identifying Different Size Japanese Knotweed Plants 🏡 Identifying different size Japanese knotweed plants involves recognizing the distinct characteristics of this invasive weed at different stages of growth. In early spring, the plant emerges from the ground as small reddish-pink buds that soon develop into shoots with distinctive purple-speckled stems. As the plant grows, it develops large, shield-shaped leaves with a pointed tip and a flat base, arranged alternately along the stem. The leave