I have a hard time using b&w on a glorious flower - but I'm trying to learn. I'm trying to learn that this still works and conveys the beauty of a flower.
To me B&W makes a statement. It may represent a contemporary feel or street photography or something gritty. A beautiful flower like this hibiscus , IMHO, loses some of its impact in B&W without gaining an equal return. That being said, I think you are great for trying new approaches.
I agree entirely with Allison @allie912 and could not put it any better myself !! Why take away the beauty of colour which God has given us in all natural living things in his creation !! B/W is ok for brick and mortar and other man made items and sceneries !!!
I like b&w flowers. I think that there are times when color can be distracting. I posted 2 flower shots today, one color and one b&w. I think each of them called for different treatment. Guess it's a matter of personal preference.
One of the categories in our yearly county fair is b&w flower - like you, I've always had a problem seeing any point in a lovely flower shot that isn't in color - but I think I'm going to try a passion flower this year in black and white hoping that it's rather unique details will make up for its lack of color. This one brings your eye to the details nicely.
Absolutely the flower still has all the shape and form and structures and the little falls of pollen... just not the colour. It definitely still looks beautiful.