To prune or not?

I live in Upstate NY...over the summer I planted a weeping cherry tree and 2 sand cherry bushes(shrubs). My question is, should I trim the sandcherrys now( they have some shoots that have grown to about 4ft tall) or should I give them the winter and trim in the spring so that the root system has had a chance to take hold? Would I kill them if I trimmed them now? As for the tree, should I also wait on trimming that too? Or if I wait till the spring, will I be cutting the new growth off? Any info is greatly appreciated. Thank you CG in NY