Hi Stargate and welcome to GoY, unfortunately your question is totally unclear 'could ivy have done' WHAT?

if this question is linked to the ceanothus question then I'm afraid it looks like it has perished.
I have taken several Ceanothus plants from sale at my garden centre that just haven't survived the winter.

Steve's right, Ceanothus is a bit tender and may well keel over in a hard winter, especially in an exposed position. As for the ivy, if its growing at the back of your hedge, you've a problem - you need to cut it down and get the roots out, and it doesn't sound like that's going to be possible, so all you can do is cut and pull off and out as much as you can. You can try painting with glyphosphate, but I've never found it particularly effective against ivy.