Posted: 06/10/2015 at 18:20
I should think it would recover well if you give it a good soak now to re-hydrate it and then a good feed in spring. I wouldn't prune just yet as any dead top growth will take the frosts and protect the rest of the plant. However, when growth restarts, I'd tidy each stem back to a pair of healthy buds.
When you do plant it out, make sure it gets a good deep hole and is planted at least 3 to 4 inches deeper than it was in its pots as this encourages extra stems to grow. Incorporate some well-rotted garden compost into the hole and the soil you use to back fill and make sure it gets a good feed of clematis food every spring.
Train the stems as horizontally as possible to encourage flower power.