I was curious enough to do a bit of digging to find out which "Elephant's Ears" run rather than form clumps. Apparently the runners are primarily but not exclusively in genus Colocasia, including but not limited to some C. escuelenta hybrids, C. antiquroum Illustris, C. nancyana and a handful of others. That was the extent of my investigation, but I am sure there is lot's more information out there.
I don't have any of those to trade right now, but thanks for learning journey.
I wonder if that is something like I had once in my pond? They were not big but they spread by runners and I loved them! Sure do miss them when when I did not get the plant out soon enough before the first freeze! I had the main plant in a small pot and the runners came out the sides.
They can be that! When I planted some in the ground in a front bed I thought I was planting Black Magic .. turned out to be the Black Runner and they were shootin out babies from everywhere! Had to go out every couple of days and cut them out. Mine are staying in containers.