In a prior blog I spoke about the fact that the root brains of a plant can communicate with each other via electrical and chemical signals. Plants speak with each other as well, in much the same way.
Tree roots vibrate. They send messages to those around them when water is scarce, they are under attack, or in need of minerals. There is a network of mycelium that spreads for miles below the ground. We tend to think of this network as generic, but different species exist as can be seen when the fruited bodies appear that we know as mushrooms. Some types of mycelia will attach at the root tips while others will go more into the main body. With the help of mycelia, plants can send messages and mineral resources to nearby offspring and other trees who are in need. The mycelia get nutrients in return for the resources gathered and shared. This leads to a better survival plan for all. Environments that have had most of the trees and understory plants removed will have a harder time surviving when conditions become difficult. Root damage and chemicals can also lead to problems in communication with other plants. Plants also emit chemicals through their leaves. These chemicals relay messages to other plants as well.
Plants speak, but in a language that we as humans are just beginning to key into. Their language is so different and their means of living are so different from humans, animals, and insects that we have overlooked plants as intelligent.