Hey babs,
I have several garden beds that have become overcrowded.
I plan to enlarge one in the front yard and use the
divisions from the overcrowded beds to fill in. It's
already in the 80's here so I'm waiting until the fall.
If it's already very hot there I'd wait. If it's not
to hot and the plant will have to time to get established
than go for it. Good luck.

best to wait....
if you just can't wait, put up a form of temporary shade for the transplants (prune a branch from a bush or tree and set alongside the transplant for shade) and be prepared to water, water, water.