In the past few decades, progress has been made in various areas of plant communication studies.
It's now confirmed that individual plants can 'communicate' with each other by various means. e.g. by :
Although it has now been confirmed in multiple studies that many species of plants can 'warn' each other of problems with drought, predation etc, many details of the complex underlying mechanisms behind stress cues and their generation / reception remain unknown.
An extensive article on plant communication in general can be found at : Wikipedia
Also see : Electrical activity in plantsplugin-autotooltip__plain plugin-autotooltip_bigElectrical activity in plants
Electrical signals within plant tissue have been studied since the 1800s. Charles Darwin was interested in possible electrical signals in the Venus Flytrap mechanism (which is still not completely understood). In the 1920s Jagadish Chandra Bose investigated what he called