Have you grown clematis in your location previously? A zone 3 climate is pretty limiting......most sites will quote a zone 4 as the lowest zone most hybrids will tolerate.

I'd also like to know the size of your circle. If either of these vines are hardy enough for your zone, they could easily overwhelm a support of that small size. And you may have difficulty training them in a circle, as they want to grow UP, not around :-)

You could easily grow any number of annual vines on that support for summer long color.

I did grow them with success at my other home. Same exposure. I had good luck with Jackmanii, Polish Spirit and Betty Corning. I underplanted with daylilies. I tend to like the vitI cella’s.

Circle is 64x64.

The circle weighs 70 lbs and it has 25.5 inch spikes you drive in the ground. It’s a substantial piece.

Check out venosa violacea and prince Charles. Both on my list to get when I have more garden space. I also love your trellis. So unique!

WWE