Hear On The Grapevine Meaning

(idiomatic) to hear rumors; to learn through friends of friends

Example: 1996, Janette Turner Hospital, Oyster, Virago Press, paperback edition, page 124
  '[...] But most of me mad dad's crew took off to American from what I can make out' - he's talking too much, he has to stop - 'from what I hear on the family grapevine, that's where they went, New York, their loss as far as I'm concerned, don't know what they're missing, eh? [...]'