Dieback can be caused by many things, but basically it is fungus which has got into part of the rose and that part is dying back. If a cane starts to dieback as soon as you get the rose, it is the garden centres problem, not yours. Take it back and get another or a refund. If it starts to dieback in the spring, the cane may have frozen and the fungus gets in and it travels down the cane. When windy, the thorns on a cane could have rubbed and again the fungus gets in. There are two main types of dieback fungus. One likes the warmth and the other doesn't mind the cold. So in the spring, the ones that like warmth often take over for the cold ones. When you cut the cane back, make sure the centre of the cane is a pale green with no sign of any brown colour. Just keep cutting back until all the brown has gone. Save the bits you cut off because I think it would be a wisdom to take that rose back. It went black too quickly so it isn't anything you have done.

Hi Sharon,

im not sure but i have the same problem. Alot of my roses just die back until theres nothing left. I just had this problem with Elina this passed summer and now suddenly with ingrid bergman. Both on fortuniana. I was horrified to find it happening now to my Moonstone too. The die back starts at the bottom and then everything from the bottom up dies. Moonstone now only has one good healthy cane left and i have no idea why. It seems to affect my HTs more than anything else. Ive never had it happen with my Austins unless they are on Doc huey and older than three years which I then blame on the root stock. (Dr.H doesnt live long down here). I remember reading something on a pamphlet that i got at Harissons Roses in Tampa about something they spray for dieback. Ill see if i can dig it up. Maybe Kubla can chime in. I think its a florida thing.

BTW its not from cold for all the northerners. We live in south Fl. Not even a frost. But heat and humidity can be a problem.