Question
This message comes from Switzerland.  We had a wonderful old rose that climbed a good 5 to 7 meters against the house in different directions and produced hundreds of flowers.  It must have been more than 25 years old and about an arm thick at the bottom.  In mid summer, the flowers suddenly dried up and the leaves did the same some time later.  Branches gradually turned black and by the end of the summer the plant showed not more sign of life.  We waited to see if there would be any sign of life in spring, but the plant was completely dry/dead. The roses growing a few meters are remained healthy.  We could not spot any of the typical fungal lesions on the leaves.  Any idea what has happened?

Answer
Most rose books concentrate on the well known rose diseases but because the rose is a member of the apples cherries, plums etc family ands,  in rare cases, is subject to the same diseases. If a rose is growing normally and then suddenly fails, it is usually caused by a problem in the roots which has been there for some time but not noticed. The other possibility could be the roots were slowly drying out. As I can't see the rose, here are a few suggestions that might have caused the death.
Look at the base of the rose just under the soil to see the following. Tumour like growth on the roots or even at the base of the rose. These are caused by a fungal infection and the rose will produce poor quality foliage and blooms and then slowly weaken and die. Verticillium wilt is a soil borne disease which inhibits the rose's ability to take the water and nutrients up from the soil to the leaves. The clue to this disease is that the leaves will wilt and die from the base up. In regards to your roses suddenly dying. There is always some moisture in the rose canes and even through the rose is nearly dead, it is enough water to push out some weakened growth, but the rose has actually died at the roots and so when the moisture is used up, it then suddenly dies and gives the appearance it was alive before dying. It would not be a wisdom to plant another rose in the same area before removing as much of the soil as possible. The fungus and the bacterial which caused this deadly diseases will remain in the soil unless removed.