What is the name of the flower that blooms once every five years?

I’m not aware of any such flower. There are a number of plants that rarely bloom, but none of that long of a repeating schedule.

Here is some additional information that you might find useful: http://bit.ly/jAMgOv

The only other plant that you might be thinking of is the ‘Corpse Flower’, which can take many years for its first flowering: http://en.wikipedia.org/wiki/Amorphophallus_titanum