Since the 70’s people have been talking to their plants and playing music for their comfort! They figure that plants grow better if made recipients of verbal nourishment and a bit extra CO2. There was an even bigger belief that plants are gentle, peace-loving, tolerant organisms.
But … Scientists have discovered the truth; some plants are stone-cold killers!
One of these plants is the Spotted Knapweed; it has a secret weapon, its roots produce a chemical that kills others plants, and this chemical called “catechin” triggers the production of free radicals, which pass from the roots upward, activating a wave of cell death. Which means it causes others plants to commit suicide!

Plants may also communicate with one another. In the case of the Knapweed, the message is “You die now!”, but sometimes there are other messages like “put up your defense, there are insects attacking!” or “there are mites attacking, lift up your defense!”, which is the case in Lima Beans.
So, next time you are in the garden or forest, maybe you should look over your shoulder!