. What an odd question? Do you classify a plant as a persona? I would, simply because it is more trainable than a human being. In the animal kingdom we find the need to communicate with their kind exists, and they do so in strange and diverse ways. How about plants and how do they communicate then. In Japan, there is a word called "sonen" in their vocabulary. It means your vibration or aura as some call it. The nature of your feelings affects the color of your aura; negative vibrations, illness color it in darker tones, the worse is black. Positive vibrations associates with the bright colors, the best is red. Plants are sensitive to your sonen and respond accordingly. What do you mean when you say someone has a green thumb? To me it means you have a positive, beneficial relationship with your plants. A farmer with a cheerful disposition and a deep love for plants is bound to raise robust crops than one who is grouchy and hates doing his daily chores. In gardening he is not the winner if he brings forth the biggest bumpkin, he is already a winner if he is happy with his plants. In my case I am happy with what I do with my plants (therapeutic benefits), and nothing another botanist can do or say that can detract an iota of joy that I get from my plants. I wonder if the UBC Psychology Faculty had done any project dealing with the psychological needs of plants.
This subject is addressed in The Skeptic's Dictionary: A Collection of Strange Beliefs, Amusing Deceptions and Dangerous Delusions by Robert Todd Carroll: plant perception (aka The Backster Effect)
another way to look at it is are plants intelligent http://aob.oxfordjournals.org/cgi/content/full/92/1/1