Have you ever seen blue roses? Arent they made artificially? Put in to soil and then given some coloring?
I've seen these little bottles of color that you put in food to give it color..
Isn't it possible to put a little bit of that in a liter of water and the feed it to the "Bonsai tree" instead of normal water?
Then you could try, maybe you could make some artificial Purple haze or somehting!
What do you think? Could it die or something? Or maybe has someone already tried it?
could be worth a try if your having a SOG, just feed the colored water to one of them..!