During the creation of this character author of the book, Steinbeck, heavily relied on stereotypes. And after a while, you will know what we mean under those words.
Rose is the eldest sister but the third child in Joad’s family. At first glance, we see that she is very cute, kind and sincere. She got super-happily married to a 19-year old boy Connie Rivers and stayed for some time with his family. Moreover, she is pregnant – and here is a stereotypical behavior the author gave her. We all know that women transform while waiting for childbirth, the same happened here. She became very secretive and mysterious woman. She sometimes complains that she feels not good, that she wants something salty or strange. Everyone was helping her giving everything she wants. During the whole story, she seems to be the only person who retains a sense of humor, and optimism. Her dream is to be a middle-class woman with her husband and child but becomes paranoid and disillusioned when her husband abandons her upon reaching California.
However, Steinbeck used all those stereotypes to get Rose of Sharon and us to the bad ending, to things that will happen with the heroin the future. Unfortunately, her child was born dead, but when they found a family who was starving, she decided to feed their child (adult one) with her milk. And that was the main thing which saved him. The act of helping someone, especially a grown man is something none can expect from Rose of Sharon. So, we see that at the novel's close, she represents life-giving force.
Rose of Sharon Joad Rivers in the Essays