Zephyr lilies are very easy to grow, though, correct, they will not be hardy in the ground for you. Pot them up into good potting soil. They would be nice mixed in with other plants, I think, as their foliage is grassy. I am not familiar with sulphurea, but have reginae, another yellow one. They start blooming in mid summer here, usually three days after a rain, and repeat until frost. I should think that if you let them go somewhat dry in their pot, you could trigger blooms with a good watering.

Since I do not grow them in pots, I cannot advise on over wintering. Perhaps someone else will.