Taking over the world, one iris at a time

Yellow flag irises are popping up all around our pond. In the foreground is one that came up this year (from seed?) in a dry spot on the near side of the pond. In the background you can see the mama (papa?) of all iris plants. It grows in shallow water and now stands taller than me! Believe it or not there's a waterfall behind it!

Do you think in a few years the entire pond will be overtaken?