Her appearance is incongruous to the setting. She is daintily dressed in a white suit with a fluffy bodice, necklace and earrings of pearl, white gloves and hat, looking as if she were arriving at a summer tea or cocktail party in the garden district. (1.14)
This is a fitting initial description of Blanche, since she does indeed spend all of the play feeling "out of place." What’s interesting is that, rather than adapt to her surroundings (which, amusingly, she claims while talking to Stanley that she is very capable of doing), Blanche tries to alter her surroundings to suit her persona.