The white rose family hierarchy in descending order are
- Rosa Gigantea
- Rosa Gigantea en bouton
- Rosa Gigantea en bouton petite soeur
At the beginning of the series, Sei is Rosa Gigantea and Shimako is Rosa Gigantea en bouton. Unlike the other rose families, the white rose family only consisted of two sisters. Noriko becomes Rosa Gigantea en bouton after Sei graduates, and Shimako succeeds her as Rosa Gigantea.
The rose families have different characteristics that are representative of their family namesake. The sisters either have similiar personalities or they relate to each other in a special way. The white rose family exhibits a blend of melancholy, stubborness, and independence. They all share feelings of being different from their peers, hence their solitary nature. They are, however, very loyal to their sisters. When white roses are alone together the masks come off.
The relationships among the white rose sisters are very special as they're unable to relate to a lot of their peers. Sei and Shimako had the most complex relationship of all. They are said to have a cold relationship because unlike the other sisters, they're not very close, or at least that's how it seems. Sei even says that she doesn't talk to Shimako much. They aren't dependent on each other because they're "too much alike", but they always put each other first.