You can 'green house' them, and see if that doesn't work.

If it were earlier in the year, you could use plastic bags and cover the entire bush after watering it so well you think you are going to drown it. Given it is closing in on July, I would make collars out of paper grocery bags and fill them with mulch, peat moss, anything which is going to stay moist. Cover the entire bush so just the tips of the canes can be seen, if at all. Water them very, very well and keep them watered. You can remove the collar and mulch when strong new growth appears. How this helps.