The OP should just ask others in the department what’s normal. In my experience, grad students did not bring the host a gift and if they had, flowers may have been considered an atypical gift for a man and wine could potentially offend someone who doesn’t drink.
I’m not sure you need to take anything although nice thought. To me the most important thing would be a note or email after the fact thanking him for nice evening. If you do definitely consumable.