Two of my passions are gardening and music. It makes for crazy summers, juggling playing at festivals with gardening work. I was recently intrigued to hear that plants actually make sounds, (and not in the 'have you heard that carrot scream' retort to veggies) and how there were actually people who believed that plants could control those sounds to communicate and even make music.
In Piedmont, Italy, there is a community of 600 people living in a community which is famous for having created the underground 'Temples of Humanity' http://www.damanhur.org/en/art-and-creativity/temples-of-humankind. They have created a MIDI interface which translates the low level electrical signals from the roots and leaves of plants into sounds. If one believes in plant consciousness, the plant is actively hearing these sounds and modifying the electrical signals it gives out, in order to change the sounds and so communicate with humans. If one doesn't, the effect could be charming, depending on the sounds used, but lacks the intentionality that would make it music.
Sometimes when I improvise with a group of musicians I know well, I can feel that it is completely instinctive, that I am not aware of what I am going to 'say' next, but of course what comes out is a personal expression of the musical cultures I have been exposed to. I imagine that if a mic'd up plant was playing in the same group, the humans would actively respond to the plant but the plant wouldn't be making musical 'sense'. But maybe I would read intentionality into the sounds it was making and be convinced of plant consciousness if I tried it! Or perhaps even if not, I could be being speciesist not to call it music? I certainly wouldn't trust what my houseplants would want to say about me...
Monica Gagliano, a plant physiologist from University of Western Australia, discovered that plants can change their behaviour based on sounds alone, in an experiment with chilli seedlings grown in a box that sealed from scent, but not from sound. The chillies' growth is usually impeded by the scent (or chemical signals) of fennel, and the seedlings in the box next to the fennel plants apparently grew far faster than usual. This seemed to be pointing to the conclusion that the seedlings 'knew' the fennel was there because of the sounds it had heard and were trying to get a head start before the fennel had its chemical effect. It would be interesting to see how plants would respond to being grown in a soundless room (anechoic chamber).
Plants do make popping sounds when they are under water stress, so perhaps other plants can 'hear' them from far away, in a similar way to those chilli seedlings and make chemical changes to reduce water loss. However, this may not be an attempt to 'warn' or imply the intentional communication of information.
Plants and animals including humans give off chemical signals all of the time, and also tiny sounds which are unconscious and removed from language or self-awareness, so it doesn't seem odd to think that sounds are part of the picture in plant communication, even if they are secondary to chemical communication. As sound is vibration, nothing is entirely silent, perhaps with the exception of a black hole, or anti-matter. Are the sounds that plants make meaningful? I think a more relevant question is: 'Can we learn something more about the world by studying the diversity of sense perception plants and animals possess?' In which case, I think the answer's 'yes', but perhaps without the anthropomorphism.
For the full article about these intriguing scientific experiments, in far more detail please read https://www.livescience.com/27802-plants-trees-talk-with-sound.html