clematis problem not seen before

I have a clematis that all of a sudden started to die back in one section last week. The leaves have gone a dark purple/dark green colour with a copper coloured discolouration on the tips moving towards the petiole. One the backside of the leaf there are really small black shiny spots, almost like tar spot. The leaves themselves have gone leathery and remain attached to the dead stems. The tips however are brittle. The veins of the leaves have gone a silver colour but is only visible on close inspection.
The stems themselves have gone a deep red colour on the areas that are dieing.
I have seen clematis wilt before and Im not convinced this is the problem. The plant was fertilized last month but it was the first time it was done since purchased last year. Im not sure if the problem is fertilizer burn, spider mite or a virus even. The markings on the top side of the leaves almost look like spider mite damage but Im not sure.
There is a clematis planting beside the one that is ill and its perfectly happy.
Can you please advise me on what may be the problem please?
Much appreciated
Thank you
Joy

 

Read about clematis wilt.

 

I have read about clematis wilt, and am familiar with the signs as I came across it a number of times in the UK.

The new growth on the clematis has not wilted, which I would have expected, and the colouration on the leaves I see is not the same as that I have seen in the past. Maybe it appears differently in Canada than in the UK. I am leaning more towards wilt as am not sure what else it could be at this point. Its the only problem I know that can hit so quickly.
Will have on keep an eye on the rest of the plant.

 

Did any-one in the area use a lawn fertilizer with herbicides in it? Or Killex? (2,4-D,mecoprop and dicamba)

Clematis is in the Ranunculus family along with the creeping buttercup we have in some of our lawns.
I have seen a neighbors lawncare techniques kill off prized clematis over the fence line before.

 

I looked but missed the statement in the original post that you thought it was not clematis wilt.