From Bolwer Wines:

"Rosette" has a more complex soil, and is much harder to work. The plot slopes up to a 40% incline, and the vineyard can roughly be separated in three distinct parts: the very top is eroded materials over hard Portlandian rock; the mid-slope is directly over Kimmeridgian marl, which can quickly suffer from drought. Finally, the bottom part is rich in dense clay with some limestone, resulting in later ripening. They usually do two harvests there, sometimes two weeks apart. They consider it their best plot."