First off, the things I'm about to quote here are not well-recognised scientific sources, and I know very little about botany - but I think it's interesting
I got the following from
http://www.cogreslab.co.uk/plants.asp
Telepathic Plants
It is now established that different light frequencies have a fundamental effect on photosynthesis rates. This must pave the way for the heresy that plants can distinguish between these frequencies or between others outside the visible part of the EM spectrum, and therefore the rudiments of communication are available to them. If one’s feet are scarcely on firm terra scientifica at this point then the claims made by Cleveland Backster, a foremost US lie detector examiner, lift them off its surface! Backster used his polygraph lie detector on a house plant Dracaena massangeana and found its needle varied when he put into his mind the intention to dip its leaves into a hot cup of coffee. His subsequent investigations, covering over 25 plant types, were eventually published in 1968 with the title "Evidence of primary perception in plant life" in the Intl. Journal of Parapsychology, of which some 7000 reprints were requested. One has to ask whether he was influencing the polygraph directly himself, and the plant may simply have been a passive amplifying receiver.
Replication and scepticism being the twin cornerstones of good science, it was not long before others tried to see if there was anything in Backster’s astounding claim. Among these was Pierre Paul Sauvin, a New Jersey electronics engineer, who later claimed to have instrumented a small plant to control an electric train set’s direction, using philodendron as his model. Like Backster and Gurwitsch he found that plants reacted most strongly to the death of living cells in their environment, and even most consistently to the death of human cells. The effect appeared to be observable even over large distances. Hans Berger, whose lifelong ambition was to find a physical basis for telepathy, would have been proud of him.
Another plant sensitivity investigator was Marcel Vogel. Vogel developed a passion for bioluminescence in the 1950s, and built up a company Vogel Luminescence, which developed the red colour seen on TV screens, fluorescent crayons, a black light inspection kit for tracing rodent pathways, and then soldthe firm to IBM to concentrate on research into liquid crystal systems and optoelectrical devices. His book Luminescence in liquids and solids and their practical application was almost a standard textbook at the time.
From this fairly down to earth background Vogel was enticed into researching Backster’s claims. He too found that he could influence the plant at a distance, even upto eight miles away. He concluded eventually that
"A Life Force or Cosmic energy surrounding all living things is shareable among plants, animals and humans. Through such sharing a person and a plant become one! This oneness makes possible a sensitivity allowing plant and man not only to intercommunicate, but to record these communications via the plant on a moving chart".
Out of many I select one particular research group involved in these bizarre experiments, Randall Fontes and Robert Swanson from California, that easeful acceptor of unusual ideas. At Stanford Research Institute they collaborated with Dr. Hal Puthoff, a physicist, to discover an electric potential travelling from cell to cell in the philodendron. This is actually not surprising in view of the communicating gap junctions which are known to exist between cells in most multicellular creatures. The big question is whether these potentials can also act at a distance when chemical communication is made impossible.
The article goes on to describe further experiments that have been done.