Abstract: A process for increasing plant growth and productivity comprising treating the roots, stems and/or foliage of the plant with .gamma.-aminobutyric acid. In a preferred embodiment of the present invention, the plant is further treated with a readily metabolized source of carbon along with the .gamma.-aminobutyric acid. The present invention also provides for a process for increasing plant growth and productivity comprising treating the roots of the plant with .gamma.-aminobutyric acid and a process for increasing the rate of root formation in a plant comprising treating the roots, stems and foliage of the plant with .gamma.-aminobutyric acid. Further, plant growth is increased by application of mixtures of .gamma.-aminobutyric acid and succinic acid, preferably synthetic succinic acid, in a suitable carrier to a plant.