It depends on which clematis you have and what hardiness zone you're in as to whether or not they need to be in a greenhouse for the winter.* Pruning is done by what pruning group they are.* Do you know the names of your clematis?
For pruning groups you should be able to figure out which is which from here.* Scroll down a little more then half way.
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant.