Yes its certainly true.
Pick two similar leaves of any plant and keep them in your room at two feet distance. Talk good words to one and bad word to another one and you will see the difference in two weeks. Its now widely called as perception science, yes plants do have a memory power and it can able to react to their surroundings and environment that also includes human!! Plants also possess what we know as consciousness in ourself, which was proved by Jagadis Chandra Bose in his experiments, those results can be found in his book Plant autographs and their revelations during 1927. Most of the plant memory researches are being carried out based on Boseian concept...