This English expression is not commonly used in spoken language but can be found in many literary works. It can be used interchangeably as “to hear it on the grapevine” and “to hear it through the grapevine.”
The expression is used to denote the hearing of rumours about someone or something. It is used to suggest that the information was not verified but was heard through an informal contact.
The term ‘grapevine telegraph’ was first recorded in a US dictionary in 1852. This was only 8 years after Samuel Morse sent the first telegraph. It is suggested that the word “grapevine” was used as the invention of this new technology was compared with winding and twisting the tendrils of a vine. It is therefore believed that the current expression which is used in an even more metaphorical sense relates to the fact that hearing something “on the grapevine” is the act of hearing something which has gone through several mediums before reaching the listener.
An example of this expression can be found in the title of an article in the New York Times; “I Heard it Through the Diet Grapevine.” The article goes on to talk about a man who tried out some diets which were popular among his friends which they had told him were successful in order to lose weight.