Z. grandiflora is dormant in winter, with no leaves. These bulbs must have been dying of thirst during the summer and resurrected with the first autumn weather. Of course this is not encouraging for a plant to be forced to grow in the opposite cycle. If seeds are available they are very precious as one could obtain clean stock from them.
Yes, Brian and others mentioned seeing them in China. Someone even published those plants as a new species, no doubt without ever wondering how a genus only present in the Americas would appear out of the bolt in Asia.
Z. candida is evergreen but its dormancy is in summer. It is a marsh plant and can be grown in a pot with a container with water (a dish? a tray?) below. Offsets freely.