My mother tells me that these beautiful flowers which grow as a big plant are called in Italian “Ieri, Oggi & Domani”, thus the English translation. This name refers to the colors of the flowers. When they first come out are dark purple (Yesterday), the next day the color turns blue (Today) and end up white (Tomorrow). So at the same time you have the three colors present.
The original name is Brunfelsia.
SunFreeStar 