I have heard news stories about this in the recent past, but I still can't wrap my head around it. I would like to believe they can, but how? I'm just not understanding that part.
...and they can also "bully" each other as well given the various allelopathic capabilities of some plants.I think they communicate with one another by putting out certain hormones if I'm not mistaken. They secrete these into the soil through their roots. It makes sense if you think about it. Plants could use it to warn their neighbors about the shade or pests before the others suffer. Then the others would know to start "moving" in a different direction by putting out new branches or shoots. Or maybe it's a hopeless situation and the other plants will know to reallocate their energy into making as many seeds as possible to continue the survival of the species. Everything a plant does takes energy, so it makes sense to make the most of it.