Plant consciousness.
Lindy, Lindy! Don't you think that if we could communicate with plants farmers would have been able to avoid famine, drought, crop diseases, locusts, etc. We've been farming for ten thousand years now and it's still a crap shoot. People danced for rain and sacrificed virgins and their first-born, too. It didn't work either.
We know plants don't think (like animals do) because if they did, it would give them advantages and they would evolve higher consciousnesses through natural selection, just as animals have: in general, the more complex they are anatomically and physiologically, the smarter they are.. As far as I can tell, all plants are equally dumb.