I, luckily, don't have deer problems, but 2 years ago I accidentally .. Trimmed?
one of my rose bushes with a weed wacker. I was using it to trim down the weeds/grass around the bush and BZZT!! took all the canes right off. I was absolutely stunned at what I had done. Luckily the rose *did* come back... But other than trimming off the winter kill (which is usually 1/3 to 3/4 of the poor bush, depending on the winter) & deadheading, I don't trim at all.