I can't find anything on this plant online. Is it native? Invasive? Harmful? Poisonous? Benign? And what should I do?

Reporter
June 9, 2014, 3:28 p.m.

Hi, Kyle. Sorry to take so long getting back to you. That looks like old man's beard to me (Clematis vitalba). It's definitely invasive, but has become so prevalent in the Portland area that few agencies are tackling it systematically (though many do on a site-by-site basis). From what I've seen, it create more issues from light-exclusion than from weight (like ivy), for a variety of reasons. It's also wind-borne (unlike ivy) so it's moving relatively quickly. I've never heard of it being poisonous.

There are several ways to manage it (and I'd recommend managing it!). The first goal is to separate it the foliage from the roots by cutting at the base and then again about 6' up. That kills off the stuff in the canopy; that 6' gap prevents new growth from climbing quickly into the canopy next year. Killing off the rootstock is the second goal. Digging will probably still be effective before the soil dries completely out; there may be herbicide options, too. Feel free to contact me directly (mitch.bixby@portlandoregon.gov) if you wanted to talk about that or any other aspect of invasive management.

Thanks for your email.

-Mitch

Mitch Bixby
June 30, 2014, 2:35 a.m.