I have PRG peppered throughout my newly renovated *** the lawn. It was new last fall and this year it filled in perfectly. but now, randomly I'm seeing these 2 inch circles or bunches of perennial ryegrass. I've begun digging them out which didn't take too long because my yard is only 6000 ft.² my question is, How do it get there , and how do I keep it from coming back. is this a perennial or annual?