Janet Devereaux-Blackmore is Blanche Devereaux's eldest daughter. She is mentioned throughout the Golden Girls series, and appeared in the episodes Home Again, Rose: Part 1 and Home Again, Rose: Part 2. She is the mother of David, Melissa, and Sarah. She is married to Michael Blackmore, who Blanche refers to as "The Yankee."
Janet is often mentioned by Blanche (often when she reflects on her children) that she has a troubled relationship with her mother.
In one episode, "The Golden Girls," Janet has David stay with Blanche and the girls because he has become too rebellious. Sophia eventually slaps David across the face for his disrespectful behavior. Outside on the porch, David tells Blanche that no one ever hit him before, and that his parents spend too much time fighting and he feels neglected. The next morning, David is given a long list of chores to do as punishment.
When it is time for David to return, Blanche calls Janet and after exchanging pleasantries tells her that since David was so happy living with the girls, that Blanche has decided to keep him and raise him herself. After Janet quickly disagrees, Blanche immediately says: "Don't you take that tone with me, Missy...Yes, I realize you're his mother...Well I suppose I can't stop you if you insist on coming and getting him...But you let me tell you this. If you and Michael don't straighten up and give that boy the love and attention he deserves, I will kick your uppity butt til Hell won't have it again!" After Blanche hangs up the phone she says she meant every word of her threat and would love to raise David as a way to make up for the messy relationship she has with Janet. After that, Janet has David join her and Michael in Hawaii where they can rebuild their relationship from scratch.
After Blanche became close to a baby in And Then There Was One Blanche called Janet up asking to come and visit, but clearly Janet doesn't want Blanche to visit, but after she hears Blanche's feelings, she finally allows her to visit on the weekend.
She is mentioned again in the episode Mother's Day while everyone is waiting by the phone for their children to call them, Blanche hopes but does not expect Janet to call her. Just as she is about to leave the room, Janet calls and wishes her mother a Happy Mother's Day.
She visits the girls in Home Again, Rose: Part 1 and Home Again, Rose: Part 2, bringing in her youngest daughter, Sarah to visit Blanche, who has become religious since Rose's surgery. Janet doesn't believe in organized religion, and she is shown to be friends with Rose's daughter, Kirsten Adams.