Several years ago I bought a climbing rose and here is what the card on it said to do to winterize it. To take chicken fencing, ( the kind that has the diamond shaped holes and is very flexible) and put it around the rose close to the graft ball. Then take oak leaves and stuff them down into the fence to a depth of about 12 inches. They help insulate the graft and keep it from freezing. Something in the oak leaves also feeds the rose as they decompose. I have done it for about 3 years now and it really works well.
When we were cutting wood, I saved the sawdust and put on my roses. I think they get nitrogen from the sawdust. I've been doing that since we started using wood for heat. Maybe the leaves give off nitrogen, too. Dooley
Love roses and this is a great rose hint, thank you. We have had several Don Juans. We live in zone 7b in the USA, so we don't have to do much with our's, but we have lots of cyber friends that live in colder zones that I will pass your advice on to them. )