Q.Is my clematis dying?
I can tell some of the vines are still green inside, but the outsides are brown and dry. Did I not give it enough water? It is getting quite old, probably 30 yrs or more. It has always been hardy till now. It is the usual purple variety.
Since your vine is well established and has been doing well, it sounds like you've been taking care of it correctly. Have there been any environmental changes, like some kind of herbicide getting on it, or some change in soil or water? If not, the problems must be pests or pathogens.
Here's one strong possibility: https://www.gardeningknowhow.com/ornamental/vines/clematis/clematis-wilt-treatment.htm
You can always take some soil, branch, and leaf samples to the Extension Service for analysis. This article will help you find the nearest one: https://www.gardeningknowhow.com/garden-how-to/info/what-is-extension-service.htm
If you decide to prune your clematis, this should help: https://www.gardeningknowhow.com/ornamental/vines/clematis/pruning-clematis-vines.htm