Question
In the beginning of summer I had beautiful rose bushes loaded with flowers..Now all of a sudden all the leaves fell off most of the bushes...Help...Any ideas?

Answer
There are many reasons why a rose suddenly drops all it's leaves, the main one being water not getting to the roots and the other is stress, but without much information, all I can offer is some of the main reasons a rose does it. Please feel free to tell me any other information that may help me pinpoint it for you. The following things can cause a rose bush to go under stress.

Some roses re-act negatively to certain garden rose sprays.
Next door neighbours using lawn or herbicides( these sprays really drift a long way)
Water not getting down through the soil to the feeder roots.
Sudden changes in weather temperatures, heat mainly
Too much fertilizer
Too much water or not enough
Spider mites
Rose bush has a fungal problem called black spot
Just planted roses usually go under stress
Because roses have bud eyes that can produce three sets of leaves without effecting the vigor of the rose bush, your roses will not die but will leaf out again.