Good news! I posted last year about some clematis cuttings that I had rooted in water. I was worried when I potted them last fall and they soon went dormant; but now they are producing new growth! (They're by a window in my basement). They're going to make it -- whew!

I want to plant them where they'll grow on an arbor I built. But the arbor has some Swedish Aspens growing by two of the corners, and I'm sure they'll create too much root competition.

OK, so here's the question: If I make a raised bed along the sides of the arbor, I'm sure the clems will like it, but will the tree roots eventually rise up into the raised bed and cause problems? Alternatively, I could create a planter box that is closed on the bottom, but I'm not sure if the clems will like that long-term, as it will limit their root depth. Any advice?

By the way, these are Ville de Lyon Clematis. Their parents are planted too close to some trees in my front yard, so they're not doing real well, either.