Better than misting the canes, stick the largest clear plastic bag you can find over the rose canes, and put soil around the bottom so the bag doesn't blow off. Put a couple of slits in the top of the bag, so there is some ventilation to let heat out. this is called sweating out the buds. I have had great success with this. It holds the moisture in around the canes, and will let some of the heat escape.
Alan
