What metaphors are used in Pet Sematary by Stephen King?

Throughout the novel one seemingly enigmatic phrase recurs in leitmotif fashion at significant points in the action — "A man grows what he can... and tends it" — and it is only gradually that the reader, as well as protagonist Louis Creed, comes to understand and appreciate its full metaphorical implications. This insistence upon the inescapable effects of moral responsibility, so dominant a feature in King's later works, may well provide the key to understanding and accepting an ending to the novel which some readers have found too horrifying even to contemplate.