When I bought this house there were irises planted, but I didn't know it. And as I was digging up turf to make a bed, I tossed all the mud/grass/roots over into a pile. I saw some kind of roots, but had no idea what they were because we never had irises growing up. The next year I had a beautiful clump of irises where I had tossed all the dirt. And these were from rhizomes that were basically just lying on the ground in a heap, not planted or anything.

Fun, isn't it. A place I once worked had a one-acre field attached. Was a construction dump or razed house or something and we were always finding little chunks of concrete and such. The first Spring I was the only one entranced by the appearance of gorgeous purple Iris along the fence line. Passiflora showed up too, but the Iris had my heart.