Q.Clematis
Why can’t I grow it? Loamy soil, zone 5, sunny area

Clematis prefer soil slightly on the alkaline side. Many NE USA soils are acidic so testing the soil will tell you if you need to amend this factor. While the leaves enjoy sunshine, the roots need to stay cool and shaded. Maybe finding the right cultivar is all you need. Check with your local cooperative extension service, Search.Extension.org for hybrids that do well in your area. Here is a detailed explanation of clematis growing requirements. https://www.canr.msu.edu/hrt/uploads/534/79846/06-Growing-Clematis-English.pdf