Our Banana Palm Turned into a Triffid!!

About 5years ago we bought a small banana palm plant about half a meter high, the huge beautiful palm leaves eventually grew to 3-4 meters high.   

In summer the plant produces this less than beautiful flower, which looks more like a triffid (I'm trying to remain decent here), and sadly once it's flowered this variety of banana palm dies. The brown flower is almost two meters long. Very strange!

BTW it doesn't produce banana's.