ive got two boys... both are too young to understand anything about drugs, but my oldest does make a distinction between flowers, weeds, plants, trees, and 'dads plants'.... i dont really plan on hiding anything from my children, they will be sat down and talked to about me and what i do... i grew up like this, and i wanted nothing to do with pot; mainly because i saw that it really didnt change my parents that much, so why the hell waste money on it? alcohol obviously made you loaded, seemed more appealing...
i've also heard of way too many kids that freak out because the found out their parents smoked on their own... they feel lied to and betrayed, and also look at you as a hypocrite for telling them not to do drugs... i think the better course of action is to explain to them the truth of drugs and the reasons why it is best to wait until you are a bit older before choosing to experiment with any of them.