Polygonum cascadense

Polygonum cascadense is a species of flowering plant in the buckwheat family known by the common name Cascade knotweed. It has been found only in the State of Oregon in the northwestern United States, in the Cascades and in the Blue Mountains.
Description.
"Polygonum cascadense" is an herb with a green or red zigzag stem up to tall. It produces small groups of white flowers with red anthers.