Very pretty!

Clematis will climb it easily, much better than wood but that is very expensive....you can use copper pipe or rebar and cattle fencing from feedstore for less.

I agree that the trellis will work well but is very expensive. Big box stores sell ones that are less expensive and look as nice. Nurseries carry trellis but again can be very expensive. For other ideas put trellis in the search box at the bottom of the page and there will be links to several threads.

It depends what you are putting the trellis up against. When we plant clematis to grow on our perimeter stockade fence, we put up panels of melon netting or chain-link like wire panels which will turn rusty and be hidden by the foliage. But if the panel is going in an up-close visibility area, a trellis is a nicer option, and this one looks pretty straightforward and useful and you won't have to worry about wood decomposing..

I agree with gardengal. Both big box stores in my area have several that are a similar height but much less expensive. Have you checked Lowes and Home Depot? Are also available at these stores online if I remember correctly.