Question
bought a Tibouchina  stam and would like to know more about this type of plant

Answer
Hi May, beautiful tropical tree, no special care needed, but it does get sparse in the winter, (Florida winter that is, non freezing) but its beautiful in the summer when in bloom, as I said, nothing special, fertilize it with a well balanced granular fertilizer twice a year, and once a month during the flowering season give it some soluble Miracle grow bloom booster. You didn't mention what your climate zone was, this is a factor.. Nick