The best time to move the clematis would either be early spring when growth is just beginning or in fall early enough that the plant will have 6 or so weeks in its new location before the first hard frost. If you are going to move the plant this fall, it would be helpful if you would take a spade and plunge it in the ground in a circular pattern around the plant perhaps a foot or two out from the plant. This may temporarily set the plant back since you will potentially be cutting the roots but it will make the plant grow more roots in a tighter circle closer to the plant. Then this fall dig a little outside this cirle when you go to lift the plant from the ground. Have your new hole dug and prepped prior to lifting the original plant and plop it into its new home. Keep it watered well going into the fall and mulched well and the plant will be on its way to settling in nicely in its new home. As is always the case, trying to move as much of the rootball is generally the best practice, but if you don't, it will just take the plant that much longer to get settled back in.

I transplanted three clems last year, one came up and the other two did not. When I went to dig in the spot where I put them there was nothing there. Does this seem possible? I keep a journal of where I move my plants so I know where I put them. Could these have rotted in the ground? Any thoughts on this.
Thanks,
Dawn