The news was spread far and wide by the "grapevine telegraph."
There is something in the north that is called “grapevine telegraph.”
The "grapevine telegraph" was an "institution" during the whole war.
The “grapevine telegraph” got to working, and soon they began to await our arrival.
My mother found out by the "grapevine telegraph" that I was going to be carried to Kentucky.
An advance tip had been sent in by a confederate on the private Chinese grapevine telegraph.
Coming from an unofficial source of rumor or news: a grapevine item/ grapevine gossip (1863+)