We need to replace our fencing but an old rose bush we’re desperate to keep and established ivy, which we’re happy to keep for privacy, is partly covering it. What’s the best time of year to do it and how can we do it to cause the least damage and maximum status quo of the plants.
Let's take an example of a climber/rambler rose growing on a fence 8 feet high and 10 feet wide. To preserve the rose as much as possible the idea is to build a temporary structure to support the rose, put in the cross supports so that the rose is independent of the fence, then cut out the fence, in small pieces if necessary. With the old fence pieces gone and the rose supported by the temporary structure, build in the new fence, tie the rose to the new fence and remove the temporary structure.
In theory this will keep the rose maximally intact. The rose will not even be aware the fence has changed. As you can imagine, the temporary structure needs to be set back from the rose on both sides to allow work "inside the box" to remove the old fence and put in the new. So it is quite a bit of work, but can be done any time of the year weather permits.
No doubt there are complicating factors such as thick growth that makes the old fence pieces hard to get to. In this case you may need to sacrifice part of the rose to get the old fence out, but your criterion is to keep the rose whole, so use your ingenuity to find a tool that will stretch inside the growth to get the old wood out.
winter of course. If just need to trim severely, should be ok (better in winter of course). If moving: The big problem is trying to keep enough roots, dont do what i have done and rip it out, somehow have to excavate retaining enough of the younger, smaller roots. Chop soil around and then under, and get Several strong people all lifting with shovels at once to move