I am not sure where you are but if you are in an area where the temperature is very hot right now, that can cause the blooms to open quickly and then fall apart. Many yellow blooming roses have this problem. I have had some that are in a nice opening bud stage when I leave for work and then are totally done when I get home from work on hot summer days. The feeding at 7 to 10 days is a bit heavy unless it is all foliar feedings. Even then it can be a bit much causing heavier foliage growth and less blooming with weak blooms when you do get them. I would cut back on the feeding and use a moisture meter to check the soils moisture around your roses. They may need more water than they are getting if it is hot where you are. They may also be getting too much water if it is not hot where you are. Too much water can make the soils heavy and thus lock out the oxygen that does actually move into and through the soils, this will cause lack lustre performance as well.
Stan the Roseman