"That afternoon my mother had brought me the roses"

Roses Still Life
Public DomainRoses Still Life - Credit: Robert Scott Duncanson
As Anne Stevenson notes, in Bitter Fame (p.48), this part of The Bell Jar is based on an incident that actually occurred when Mrs. Plath visited her daughter on her 21st. birthday, although the roses in question were yellow not red.

 According to her mother, yellow roses were Sylvia Plath's 'favourite flowers'.