General purpose compost, ok for containers?

[knackeredknitter]

Can I use this for potting clematis in a container? Should I add something to it? I have a lot of it and don't want to have to buy potting compost.
TIA

Yes, it should be fine.

I personally tend to mix it with some decent garden soil if I am planting something longer term like a clematis, as I find that otherwise it tends to dry out more easily.