In the very 1st room, get the broom ability. In the 2nd room, grab Pitch as your helper. In the 4th room, watch out for the doors underwater. In the first one, there is one stem, then in the second room there is two, while in the third there is three. Use your Pitch\Broom ability to send off water blobs which help the stems grow into flowers. Do this for all six stems. Make sure you don't accidentally step on a stem or a flower!