hear through the grapevine

The term originates from the Grapevine, a telegraph line established in 1859 running between Placerville, California, and Virginia City, Nevada. The wire was strung loosely from trees rather than poles, causing the line to sag and curl in a manner reminiscent of the vines of California grapes. By 1861, this improvised infrastructure was replaced by the Pacific Telegraph, which utilised standard poles and offered a more reliable connection.

During the American Civil War, the "grapevine telegraph" became a proverbial shorthand for unreliable or informal communication. In areas isolated by the conflict, where official lines were frequently cut or non-existent, information travelled through these tangled, unofficial networks. The phrase persists as a reference to the transmission of rumours, the accuracy of which remains as precarious as the original wiring.