I'm pretty much sure anytime would be fine to do what you're asking.

Long story short, I worked for the City of Portland Oregon's Horticultural Department and during the beginning of fall, I stuck these right into the ground as cuttings. The following year (spring) they were to be dug up and moved.

If you do it now during the blazing heat, I'd recommend they be put in shade. And 5-8" cuttings but not much longer should they be.

Dax

I would agree with Dax. Wait intil fall or after the leaves have dropped.