DaddyFish wrote: Maybe transplant those unknown plants to a separate garden area and then watch and see what they turn into rather than killing them. They may not be pretty now, but they still serve a purpose environmentally. If one or two get out of control, move them to a local forest or trim them back, just like with Lillies and other "bulb" plants that you giveawy to keep the overcrowding down. -DF
Fish, I don't think that moving them to a wild habitat is ever a good idea. The invasives destroy the natural, native growing plants and could potentially take over entire areas.
According to Oregon's Native Plant Society this one is considered invasive so no setting it free. I don't really like the way it looks so I'll be taking it down. I noticed while I was looking through the list that the Foxglove that bloomed and the Butterfly Bush I want to plant are also invasive to Oregon.
I'm surprised I didn't see that Love In A Mist (from my other yard post) isn't on the list, that stuff spreads like wildfire and is native to southern Europe. It's very pretty, but I've eradicated it from the yard too.