First, this is not the time of year to prune. You should prune in winter--say January or February, March at the latest.
Second, are you sure the roses you are concerned about are not once-bloomers? Some roses bloom only once a year. Do you know the class or variety of your roses?
Third, though I live in northern California, I have experienced some unusual behavior with some of my roses this year. Several of my plants--a 'Bowbells', 'Mme Alfred Carrier', and a couple of others which are rebloomers, bloomed only in May. I've had no blooms since. And another rose, which blooms only once a year has bloomed twice as of right now. Still a few others, like 'Belle Poitevine' which usually blooms exuberantly at least twice a year has been very stingy with bloom after the first flush. I conclude it's climate change, with the soil warming.