Question
My roses were coming out and fully leaved, they were gorgeous and we had a hard late freeze which turned all branches and leaves black.  I pruned them back and some of the bushes are coming out again, but they seem to have trouble holding their branches upright. They fall to the ground and then the branch dies. What have I done wrong? I mulched them and I fed them after the leaves were established, but branches are dying.  I have some that are blooming.  

Answer
Here's my guess: The unexpected chill hit your Roses hard, did major tissue damage.  So you pruned.  Perfect.  You fertilized to encourage new growth -- high Rose fertilizer, high in Nitrogen.  What you're describing is a Rose with TOO MUCH Nitrogen.  Is this possible?  You are clearly someone with experience with this.  I do find it hard to believe you would put too much N down for this Nitrogen-hungry shrub -- not in a form that would burn the roots, but a major dose, too much of a good thing, in a fast-food chemical kind of fertilizer that shot into the roots and up the stems with the speed of an addict shooting up cocaine into the bloodstream.

I know what you need.

You need a product sold under the Eden Bioscience label 'Messenger'.  You can read about it on the Cornell University website:

http://www.news.cornell.edu/releases/April00/FireBlight.bpf.html

This product, harpin protein, is NOT an enzyme, it's NOT a fertilizer.  It is a molecule that was found to boost recovery and inhibit disease in plants.  It's the 'recovery' part that I think qualifies certain of your Roses for a harpin treatment.  If you spray it on the leaves like you were spraying for blackspot, and soak the leaves of all your Roses, you will begin to see improvements in a few days, with no further action.  Watering is of course important, if nothing else to rinse fertilizer salts out of the soil.

I would also mulch with Manure.  Aged is preferred; carefully diluted with Peatmoss or Humus, it will steadily feed Nitrogen and plenty of Phosphorous to your Roses.  Ease up on the chemicals.  They wreck the soil structure and halt natural mineral production by microbes breaking down organic matter like Manure.

Since you're clearly informed on Rose growing, your thoughts would be greatly appreciated on this -- keep me posted, please, on your progress and results.