When is the best time to dig up/collect junipers in Souhtern California?

I’ve done so much research but keep getting mixed information. A lot of the stuff I find about yamadori collecting is about how to do it, aftercare, box, pumice, etc. However I cannot seem to find a video or article or blog that talks about perfect timing I’m collecting Juniper species in Southern California with the best success. I live out in Santa Barbara at the moment and there is a lot of common junipers there are used as shrubs throughout the neighborhood. My next-door neighbor has one in particular that’s in his property and he doesn’t mind if I take it. I am just looking for the best time to dig it out. Anyone have success in the matter?