blamoscience:

Researchers have discovered that plants have the ability to recognize their siblings through their roots and the chemical cues they secrete. The finding not only sheds light on the intriguing sensing system in plants, but also may have implications for agriculture and even home gardening.

Susan Dudley, an evolutionary plant ecologist at McMaster University in Hamilton, Ontario, and her colleagues observed that when siblings are grown next to each other in the soil, they “play nice” and don’t send out more roots to compete with one another. However, the moment one of the plants is thrown in with strangers, it begins competing with them by rapidly growing more roots to take up the water and mineral nutrients in the soil.

“Plants have no visible sensory markers, and they can’t run away from where they are planted,” says Harsh Bais, assistant professor of plant and soil sciences at the University of Delaware. “It then becomes a search for more complex patterns of recognition.”