Question
Hi, I have two double knockout rose bushes.  They are planted about 3-4 feet away from each other.  One is doing really well, the other is not.  It's leaves are turning yellow and falling off, a lot of the branches are turning black.  However, there is new growth at the tops with buds.  There is a big empty space on the whole right side where I had to cut away blackened branches.  What could be wrong.  Will the whole rosebush eventually die?  I did notice spider mites and have been spraying it with a pesticide/fungus/miticide 3 in 1 spray for roses.  But I'm not sure if they are the problem.  Your help would be greatly appreciated.

Answer
If one rose does well and another is poor, then there is nothing wrong with your soil or anything that you are doing. The problem is the rose itself. the rose sounds like it is dying because it had problems when you got it. Spider mites cause leaf problems such as killing them not cane problems. The rose has canker and this is caused by bacterias getting into a small dead area and then slowly killing the rest if the rose. Personally I would not try to save the rose as I think you will still continue to have problems with the rose. The problem could also spread to the other rose especially if you have used the same clippers on both.