We're in our second heat wave this summer (3 consecutive 90+F days) and management is difficult. We get downpours sometimes for half an hour, but
then it is 93 degrees the next morning. My strategy is to use a watering can to
soak the containers (non-roses) and let the in-ground plants fend for themselves.
However, downpours are tricky; they don't tend not to penetrate very deep.
So I'm out there dragging a hose around once or twice a week in the blasted
heat. I'm in a city park so no underground irrigation is allowed. Sigh.
(I don't really long for 12 degrees and 6 inches of snow, though.)
David

If it is allowed they need mulch.
Loosen top three or four inches before applying.
I use Cocoa Bean Hulls several inches deep, also for their mild fertilizer effect.

I love cocoa bean hulls as well, however, they can be toxic to pets, so be careful.

MbN Hmmm cocoa bean hulls...
Do you suppose they're toxic to rats too?
I do garden in a New York City park. I live
cheek to jowl with the little fellas. Made my
peace long ago. We sort of respect each other,
though I sometimes hold a hose in their
hole for five minutes or so.

RpR. Yes, the one inch of mulch that I applied
in early May is pretty matted down now. Water
rolls off it. I get pretty nice double shredded
mulch of something they want me to believe
is redwood from the parks dept. Maybe I should
break my back again spreading another inch
or so.

David, only if chocolate is toxic to rats. Not sure that anything is toxic to rats other than warfarin.

I agree, add more mulch. For in the ground plants, do deep watering. For container plants, water once in the morning and again in the late afternoon. This is what is working here for me on the northeastern shores Long Island.