Hmmmm...yea, I agree about the large bush being a Hazel of some sort. The leaves and overall form look very similar. What do you think about the smaller plant actually being a small Hawthorn tree? The leaves look similar but I don't think this one has thorns. Are there thornless Hawthorns?

Can't see the photos...says I don't have access.

I was astounded when you mentioned they are becoming invasive.......and checked it out to find that in certain localities they are. Seems they can go in this direction where summers are cool. Mine doesn't go the nice red in autumn, but a dirty gold........some amurs will. And I never have a heavy setting of samara and am just now finding a few volunteers under the tree and it's been there maybe fifteen years or more by now. Mine is gorgeous and thriving.........but our summers can be hot and I suspect it affects the reproductive capabilities.

Thank you for your comment @Shrubbish. This plant may be a climber but those bare branches don't extend much past the photo. I almost think the twisty stems look like a honeysuckle but I haven't seen that leaf before. Any ideas?