I planted what I thought was a jackmanii clematis at least 3 years ago. I thought I read that jackmanii is a type 3, but I am not certain that is what I have now.
I say that because it seems like a type2--it blooms on old and new wood.

For fear of doing something wrong, I have never pruned it (I realize that not pruning is wrong in itself!). I noticed last summer, it did not fill out very well, and the flowering was mediocre at best.

I am reading that new clematis should be hard pruned the first couple of years in the ground. Since mine has been in the ground a bit longer than that, will a hard prune damage it?

I am central Illinois, so we still have at least a few more weeks of colder weather. Can I prune now, and how far down should I take it?