Penelope is cunning, devious, calculating, and cruel, a true Blossom through and through. She also was a loving mother toward Jason and a loyal wife to Clifford, as far as we can tell, until he was revealed as the murderer. Even then, she seemed to have divided loyalties between Jason and Clifford.
Jason’s death broke her, but was she broken before that? Why is she so abusive toward Cheryl? Projected self-hatred? Why didn’t she suspect Clifford of Jason’s murder? Did she know about the drugs? It would seem that she did, because she knew that Cliff arranged for Hiram’s arrest.
Cheryl is the only family member she completely despises, which suggests that Cheryl may not actually be her child. The possibility remains that one or both twins were born using a surrogate’s eggs, with Mary Andrews being the most likely candidate. Alternatively, Cheryl may be Clifford’s child from an affair, born around the same time as Jason, and brought home by Cliff to be raised with Jason as his twin. That would explain Penelope’s hatred.
I’m still half convinced that everyone in town is a distant Blossom relation. It would explain a lot. Only the favored branches still own a piece of the syrup/drug business, and there are resentments about old and new slights all over the place. Given that the Blossom men do seem to be cursed to early deaths, the women have to be the ones in the family with the real power. That would leave Penelope at the center of that extended family web, as the new head of the syrup business. I suspect that she has some connection to every Blossom feud, curse, and scandal ever.