I would be concerned about the soil where the old clematis grew and looking to see what might have gone wrong a couple of years ago. Did something get spilled on the soil or, when you dig the soil do you find grubs in it, etc etc?

Yeah, thanks Bulbaholic............I'm beginning to think along the same lines myself.

OK, I'll dig my clematis up and plant her somewhere better then. Trouble is that after a year in the ground her roots will have spread quite a bit. I'll be careful.........

And I'll have a closer look at that soil too.

Such a great site and appreciate the help so much!

Have you been feeding the new plant?
I would think that you are past the point of transplanting for this year - it's almost certainly got new growth and you will lose this if you transplant.
I'd go down the route of feeding and building up the plant for a year and if it still isn't thriving move it when it's dormant into a prepared hole. Transplant 4-5 inches lower than it currently is as this will promote root growth. Prune back to about half its height and don't forget to feed it - a high phosphate (the P in NPK) fertiliser will encourage root growth - try liquid seaweed extract. You'll also want the K (potash) to promote flowering.

More good advice - thanks Urbanite!

Yes, I was concerned that it was too late to move it now. But there's been so little growth this year I may still be tempted.

I'll look again tonight and decide......and thx.

The best time to move is in spring just as the new growth is appearing. I moved a mature one recently (in the ground for 7 years) and so far so good. Advice is as been said, plant deeper too.