Even though much of the plot in To Kill A Mockingbird revolves around her, Mayella Ewell is one of the least-developed characters in the novel. But she has significance other than her role in the plot: it becomes her duty to fulfill the role of the pure and helpless Southern Woman.
Mayella Ewell's father Bob, a drunkard who represents the ignorance and hateful prejudice of the South, is probably the least-sympathetic character in the novel. The Ewells are Maycomb's poorest residents, living behind the town dump from which they scavenge everything from the roofing material for their shack to some of the food they eat. They make their shoes out of old tires, wash only when they feel like hauling water from the other side of the dump, and are often sick (Lee, pp. 172, 185). It's a dirty, trashy yard except for the one corner where Mayella grows her red geraniums in scavenged slop pails. The care she clearly gives the flowers may represent her desire for the finer life of a stereotypical Southern woman. Scout makes it clear that "people like the Ewells lived as guests of the county in prosperity as well as in the depths of a depression" (p. 172). The Ewells were only ever tolerated, not welcomed.
There is a big shift in sentiment toward Mayella Ewell when Tom is accused of raping her. Suddenly, Mayella is not the trashy, ugly guest at the table; rather, she becomes representative of the genteel, white, Southern Woman, something Atticus Finch calls a "polite fiction" (Lee, p. 149). In order to justify sentencing a man to death, Mayella has to be believable as a fragile, helpless woman who must be protected at all costs by the heroic Southern white gentleman. Suddenly, Mayella is not the ugly squatter from the dump:
A young girl walked to the witness stand. As she raised her hand and swore that the evidence she gave would be the truth, the whole truth, and nothing but the truth so help her God, she seemed somehow fragile-looking (p. 181).
Now Mayella is a young girl, frightened and fragile, and in need of saving.
Mayella herself contributes to this picture by crying in fear--whether mock or not is hard to tell--at being on the stand and telling everyone how she was just too weak to chop up the cabinet for kindling as her father had asked her to do. The judge responds heroically to her tears: "'That’s enough now. Don’t be ‘fraid of anybody here, as long as you tell the truth. All this is strange to you, I know, but you’ve nothing to be ashamed of and nothing to fear'" (p. 181). In her final moments in the courtroom, and in the novel, Mayella calls on the men to be men and to protect her dignity and her position as part of the privileged white class:
I got somethin‘ to say an’ then I ain’t gonna say no more. That nigger yonder took advantage of me an‘ if you fine fancy gentlemen don’t wanta do nothin’ about it then you’re all yellow stinkin‘ cowards, stinkin’ cowards, the lot of you. Your fancy airs don’t come to nothin‘—your ma’amin’ and Miss Mayellerin‘ don’t come to nothin’, Mr. Finch (p. 191).