Submitter does not have a specimen
EDRR Status: Local expert notified
the plant is Clematis vitalba, Old Man's Beard. It is on your B list. It is common in Multnomah county, however on the description in the Council information it is not noted to be in Wheeler county.
There are small growths that are along the stream next to the highway. It looks like it is in early stages of invasion and only riparian.