In t B. Midler wrote:
The soil is in fair shape, never great on that south exposure. There
is about 3 inches of permanent organic mulch. I'll use what gray water
I can, but the number of roses exceeds my supply. Any suggestions?

Come to sunny NSW, where 99.7% of the state is drought declared ;-)

Seriously, if they sell water storing granules where you live, put them
under your mulch and dig into the top soil. They swell into jelly-like
globs and hold a stack of water, then dry back into crystals again. It
will make the most of what water you do give them.

Also use a soil wetting agent to make sure run-off is zero and water
hits the root zone where it will be taken up, as well as stored away
from the risk of high evaporation.