How hardy is the cuban lily

I have had Scilla peruviana growing in a container for 4 years. I have an exposed garden in East Anglia. This year sadly it succumbed to the awful winter we had, cold and very wet. I think the main enemy of bulbs is winter wet and so if you can improve the drainage for your plant with sharp sand and horticultural grit, you will increase its chance of surviving the winter. Conversely, it requires a reasonable amount of water during the growing season!

Echo that, Lou