My nemesis, Old Man’s Beard clematis, Clematis vitalba

[JustSarahThanks]

That is discouraging. I am not sure how it works in Oregon, but in Washington they classify noxious weeds by three categories, and I think only the worst category can cause intervention by authorities.

It's a good idea to pursue contact with the owners or property managers, but if that doesn't work, you may be forced to either accept and deal with the problem or take stealth measures. Not knowing the area, I can't recommend if this is a good idea or not, but if it was me I would be researching ways to dispose of the plant. I hear fluoride works better than bleach, so that might be something to look into. Also roundup, although that probably wouldn't be effective until the plant leafs out again in Spring.

What the nice fella at the Oregon Invasives Hotline told me is that their specific role is more early detection and rapid management to prevent the spread of new, novel invasives. Things like Clematis vitalba or scotchbroom, Himalayan blackberry, English ivy etc. are already widespread and established in the region so they don't prioritize chasing down individual ones and I guess also there's no one to actually do that work. Clematis vitalba is every bit as invasive and aggressive as anything, but they're not equipped to handle every single individual in PDX city limits. Which all makes a certain kind of sense although it is disappointing and feels weird to me that they just... kind of leave these invasives because there's no point. The person I was in contact with apparently is the only one at the Oregon Invasives Hotline and it's a satellite of the City of Portland Bureau of Environmental Services, so if, say, a murder hornet turns up and gets reported he himself might actually have to be the one to sort it out.

He did have some helpful tips for removing the plant, though. Apparently if you cut the vine in two places, one at the base and one at eye level that should kill it off and then the root ball can be worked out of the ground. Sometimes in spring you get new shoots of new growth from remaining root material but that'll show you where there is more root to dig up. Assuming I get the go ahead from the landowner I'm trying to decide if I (and/or my spouse) are up for digging out a root ball on someone else's property vs. trying the stump killing treatment recommended in this thread vs. just hiring a professional and saving me the back pain.