What is the giant flower with flies for in animal crossing wild world

The giant flower only appears when you have alot of weeds in your town. It is called a Rafflesia and it doesn't do anything, and you can only get rid of it when you get rid off the weeds or water it with a golden watering can.

When I first saw this message I thought you where talking about garbage! I've never let my town get so bad and weedy.