Symbolism. Why only in "The Geranium"?

Yes, these stories are so similar that it's almost hard to distinguish them. After reading both of them I found myself preferring "The Geranium." I think I liked it better because Old Dudley was a more likable character than Tanner for me. He spends much of his time staring out the window at a geranium across the alley. The geranium, by this association, is a symbol for him. Having a flower as a symbol for him makes him a very delicate and weak character. As the reader, I felt sorry for him and almost slightly protective of him in this strange world where he feels so alienated. This weak personification of him continues when he gets lost in his own apartment building and has to be helped up the stairs by the black man that lives next door.

Even though the black man was perfectly nice to him and kindly helping him up the stairs and is even well groomed, Old Dudley is unable to get past his previous racist beliefs and see the black man as an equal. He is trapped in the beliefs that he was able to keep in the old South. The only problem is that he's not in the South anymore. He's in the North now and he would have to change his beliefs to grow. When he returns upstairs he cannot break away from his shallow beliefs. This is mirrored in the geranium falling from the window. It smashes on the ground where it is uprooted like Old Dudley is in New York. It is unable to grow anymore just like Old Dudley because he is unable to let go of his racism. Eventually it's going to die, just like Old Dudley will be unable to continue his happy life in New York.

So I think that the geranium symbolism is why I enjoyed "The Geranium" more than "Judgment Day." My question is, why did O'Connor include the geranium in "The Geranium" and not in "Judgment Day" when there were so many other similarities in the stories.