When I lived in Augusta, Georgia (USA), I was able to observe Zephyranthes
atamasco "in the wild." Their growth cycle was similar to that of Lycoris
radiata, except for bloom time. They would put up new foliage in the fall
that would grow through the winter. They would bloom in spring
(March/April). In early summer, the foliage would start to turn yellow,
then disappear. The seeds would ripen at about the same time.
The population grew in a deciduous woodland along a small, permanent stream
and bloomed every year. Winter temperatures were fairly mild (zone 8).
I'm not sure how they would behave in areas with colder winters.

Eugene Zielinski
Prescott Valley, AZ
USA