Kate, I do not know when it is a best time but I took 6 cuttings last spring and just stuck them in the 6" pot each (no rooting agent at all) and they all rooted. I have a good luck with rosemary. Sometimes I just stick it in the ground near by and they grow. I am sure that there is a proper time and method when to do that but this has been my experience with rosemary. Good luck with yours.

I took 4 just today. Do you know how or do you need help with it?

Thanks kindly Klahanie and Eileen for your feedback, I recall how to take the cuttings but couldn't remember the best time. This helps me, thanks again!