Unless your container is of giant proportions, I wouldn't recommend putting a clematis and pieris in the same pot. Pieris should be planted in ericaceous compost, clematis will do just fine in John Innes No. 2 or multipurpose - use a separate container for each plant, just to make sure they've got good root room.

Thank you Bamboo, i thought that might be the case but needed to make sure. Finding this sight has been wonderful and am so hooked onto it now. The advise given and knowledge shared by all GOY members is very helpful and much appreciated.