When I attended the Bonsai workshop, the lecturer told me that if my Bonsai starts budding 4 weeks after repotting it, then I should use some fertilizer. Was he talking about the Chinese Juniper or the Maple tree?
Once new growth can be seen, it’d often safe and appropriate to feed the tree. I don’t see a difference in terms of the species, junipers or maples, can be fed after seeing good new growth.