SOLVED. Adult fiction - title is the name of a flower; woman with selective amnesia. [s]

[Mary Kathryn]

I read this book sometime around 2010-2012. I remember part of it is a woman and the dysfunctional relationship with her mother. The main character has apparently blocked out some of her childhood memories, but remembers something when she is drunk about her mother leaving her for several months with a babysitter/neighbor. I believe the title of the book is something like a white flower?
The only specific detail I distinctly remember is that the reason the main character remembers her mother leaving her, is because she says some sort of a specific phrase while she's peeing in the bathroom drunk and realizes it's a phrase that the babysitter/neighbor taught her to say while she was being potty trained.

[essie]

White Oleander - could this be it?

[Mary Kathryn]

Yes!!! That’s it! It’s been driving me nuts all day! Thank you!

[essie]

Aaaaah score! I only know it because a friend was talking about it. Deffo going to read it now 😁