I have been curious about something for a while and perhaps someone on the forum can help. I have read that breeding a pure white Hippeastrum was once a challenge for breeders. I found this surprising, considering that there are several white-flowered species from which to start. Are these species particularly difficult to grow, or are they not interfertile with other species that are commonly grown and hybridized?
I thought you might like to see a photo of H. goianum, which I took about 20 years ago in Brazil (and long before I began growing Hippeastrum). It grows in the savannas there and tends to flower in the dry season (which is their winter), shortly after a fire.
I look forward to any insight you may have about the role that white-flowered species have played in development of hybrids.

Bill