Does this look like a baby Thai Giant? I grew one near the M. basjoo last year, raked the old mulch around basjoo, mulched with straw, over wintered and then chopped up that for use this years. The mulch in this pic.
Here's a petiole pic of an old
Yellow Calla Lily (Zantedeschia elliottiana) which I've been meaning to take for a few years.