I guess what I was saying in a way is that when you build the pond the dirt work will wipe out the vegetation. If you wanted to install artificial grass (which by the way now days looks pretty and almost real) it would be the time to do it. The real vegetation around your pond is going to be drawing its moisture / water from your pond. If you want the real stuff there is nothing at all wrong with that.
Here is a pick of a back yard done in artificial grass.
