My friend who grow it here in his garden calls it Vara de San José, however that common name is given to at least 5 different genera, none asociated with Zephyrantes. Z. candida has the general looks but the PBS page only shows white flowers. This seems slightly different, however it could be a hybrid that has been bred for pink. It is not a local native wildflower; the size of the bloom is about 7 cm wide and each scape has many flowers open at the same time. In his garden that is very close to the Nahuel Huapi lake it grows in a wet marshy condition and winter temperatures hardly drop very much below -3C. Even when it snows , snow doesn't stay for long. His population multiplies easily and is a very ornamental addition for fall flowers in mild areas. Thus I would tend to agree that it may be a rain lilly however I still doubt that it is a Z.candida. I found this link for a Z. hybrid that most closely resembles it.
http://www.plantdelights.com/ (Pink Panther)
