Those leaves are stunning. The website below suggests it is not hardy so needs to be moved in winter. Perhaps a big shallow tub of water (a washing up basin) would be sufficient to see it through the summer months. Plant it in a pond basket then move it, in the basket in to a bigger pot of compost for the winter. https://plantsforponds.co.uk/collections/pond-marginals/products/elephant-ear-colocasia-rubra-black-magic

It doesn't have to be actually in water, it will grow fine somewhere like a bog garden too, so you can start it in ordinary potting compost so long as you keep the soil always moist and don't let it dry out.

As for winter being over, well, that remains to be seen - we've had snow in April and May before, so don't put that plant outside till end of May.

I would like to think that winter was, indeed, over. I would wait until May to make that pronouncement, or are you going for the Michael Fish Medal, Shazziepx ;-))))