How big are the pots (height and width) and how long have they been in the same pots?

I have both a clematis and a honeysuckle in large pots in a sunny position and I water them every other day and they seem to be doing fine. I think the answer, or part of the answer, is to water frequently. Never let them dry out. That is the price we pay for planting in pots...time it takes to water.

I lost a clematis this year due to the dreaded clematis wilt when all parts of the plant go brown and die.previously have dealt with this by cutting right back and adding fertiliser ,like blood fish and bone and watering well.however this year even this did not work and plant died.
Perhaps you need to replant in fresh compost and keep watering.

Clematis prefer their roots to be kept cool, so try and keep the pot shaded. Because of the amount of leaf area they take up a lot of water, so this will also reduce water evaporation.