Help I D this mystery plant?

[Muckman]

Hello, I was recently given a large(ish) Colocasia-type plant from a friend with a water feature.
This plant grew out of a small pot in about 2 ft of water. The longest leaf stem is about 30 inches, & the leaf itself is 16 inches by 11 inches. My friend doesn't remember buying this thing, & thinks it may be a volunteer, like came in mud with a different plant. It was growing out of the side of a small basket pot, & the mud in the pot was sort of strange (to me) too. It was sticky & fibrous & had lots of clay in the mix. It had that almost-anaerobic funky smell, but there was almost no rot in the root system, & I even found live earthworms in this mud! The mud also had these soft little grey pellets that I have never seen before. The plant has spent two winters in my friend's pond (NW Oregon), including several freezes (but not of the root system), so it is fairly hardy. The best guess I can make now (from internet photos, etc) is either Colcasia fallax (since that grows in colder climates) or something else called Xanthosoma spp.
Does anyone have a good i d for this plant, or a suggestion I might have missed?
Are the grey nodules part of the root system, or leftover time-release pellets??
Thanks for any help!!
Muckman

 

[BKHpondcritters]

Looks like some variety of Colocasia to me. And I think you're correct about those little grey bits being left over fertilizer pellets like Osmocote.

 

[Muckman]

Thank you for weighing in!
For the record, it was doing great in the little pond, mostly with city water top-ups (pH 7.4 or greater), & limited sunlight (2-3hrs max NE exposure / maritime climate/prevalently cloudy weather), not to mention what must have been a euphoric send-off with all those food pellets!
I have temporarily re-potted the plant in a small bucket with some of my regular planting mix, & some of the stuff it came in . . . ... getting unstuck from the pot resulted in several small starts of rooted material, which will go into other random barrels around here to see what happens! Survival of the fittest. Now trying to imagine where I can make room for the Big Daddy itself.