Hi Peggy. It is fun taking over another persons garden and finding treasures blooming there. The tuber on an iris is called a rhizome and is just an underground stem that saves energy for the next bloom season. The new rhizomes stay attached to the 'mother' rhizome until they are detached. If you find them in other places it could be that one was growing there originally or a tiny piece of a rhizome was left, or dropped, when moving them. I hope the weather warms up for all the plants and people that need it.
