Ok, I first started out seeing if my Thing-O-Matic could print Tony Cervantes's flower http://www.thingiverse.com/thing:5883 . To my surprise, it did. So I modified it a little to add a base to the flower so that I could attach a stem, and then created a vase to put it in. Yes, the vase printed to my surprise also!
Print Flower, Flower_vase, and stem. Glue the stem into the flower base via acetone or your favorite glue. I decided not to create a hard and fast hole in the vase but an area that you can drill the size hole you want as you may want just the vase for something else. Once you drill a hole place the stem into the hole and glue.
The scale of the flower and vase may need to be adjusted to your requirements.