Roundup, what is not safe to spray around and please read:?

I am 56, going back to lawn and shrubs and I don't know much about shrubs, I know if I spray round up around dahlias it will kill them all by leeching. At this season in zone 7, what would be my best way to dig up a few perennials to move to the back yard and then kill weeds, smooth out and put in lawn there. I know how to do all but what to use to kill weeds before new lawn and saving shrubs,newly planted ones, or should I just dig them up too and put on hold ??? thanks so so much