Question
I have planted my roses in large wooden barrel halves, that I got from Wall Mart. I have had to treat them all summer long for different things such as dying leaves, and now mildew and black spots on the back of the leaves, can't tell if it is rust or what. about 2 weeks they all looked just great, and now they are all so sick suddenly. I have just sprayed for mildew and some bugs, but I am not so sure that what is causing this problem. I am wondering if they should have been put in the ground instead of the barrels. I have a drip system on them and they have accumulated some slimy stuff on the top of the soil so I took the drip system off and let them dry out.  They have bloomed profusely but a couple of them have sent out canes that are very long like a tree and others have sent some that look normal buut they are all on one side of the bush. Can you tell me what on earth could be wrong with them?

Answer
Roses tend to go under stress when the weather turns hot or if they are sprayed with something they don't like, even a certain fertilizer will set them off into a stress mode. Lets start from the beginning and see how you can solve the problem.
A half barrel is fine for roses as the wood doesn't get hot like a ceramic pot does so the container is fine. Use a sow release fertilizer such as Osmocote 14-14-14 and then put a mulch over the top to help keep the soil mist. Only water every five days soaking the soil throughly and then let the soil dry out a little. If the weather turns hot, water every three days. The fact that they are sending up nice long canes is a positive sign and means that whatever you are doing is okay. Yes, I know it is annoying when a rose only puts out canes on one side but that is just the rose, nothing you are doing. You can cut the tall cane back even with the rest of the bush if you want to.  It is getting to the end of the growing season in most places so I would be too concerned about the black spots. However next year start your spraying before they leaf out in the early spring and then again after the leaves have started to grow.