When I send a flower and say hi, it represents the usual masculine effort of making the first move. Just like at a bar, etc. The female (most) expect the man to make the first move [valiant; prince charming; bold...whatever]. Just like how there are risks of making the first move at a bar, etc., there are risks to sending a flower on the part of a male.
Most men will say that for every wife they get, they probably spoke to 100 females. A flower does the same thing. Not every woman who gets a flower will respond, but hey, I have never received a flower from a woman I did not flower first. Of course, the real e-mails, etc. will come after the initial contact.
You can just ignore the flower if you don't want to talk to the guy.