Hardiness of Zephyranthes foliage
Alberto Castillo (Mon, 14 Oct 2013 11:51:03 PDT)

Coming to think of it, my comments refer only to Z. flavissima original sp. from Argentina. Yes, there are other plants that are not the same species around. Something disastrous over the last years is a commercial source with no botanical training (or worst, NO knowledge of the plants) that has been giving botanical names to irids and amaryllids only to promote sales. This has led to a lot of confusion and therefore the fact that we seem to be discussing one species. Yes, my original plants set seed in hot climates like Australia but not has profusely as in the wild.

Z. flavissima can be an evergreen but the proper cycle is summer dormant. It flowers in autumn with leaves at the start of the growth (and rainy) season. This is why your plants looked unhappy with that extra flood WHEN AT REST.

As for the original question, flavissima foliage could be surprisingly hardy but it does not mean it prefers such conditions. Under cool conditions it will gradually dwindle to nothing.