My Siberian Iris has managed to invade the peony that sits about a foot away from the patch of irises.

Knowing how difficult it is to dig up these irises, I was thinking of watering the peony well, then digging up the whole area and then separating out the irises and replanting the peony stalks. Does this have any chance of succeeding?

It's curious that the irises didn't just slowly grow over. It's like they jumped over a foot and started growing. Pic to follow