"Against the fence, were six jars holding brilliant red geraniums, cared for tenderly. People said they were Mayella Ewell's"
I'm assuming that you are wondering about the importance of this quote in regards to the book.
The Ewell's are considered "white trash". They live behind the garbage dump and sift through the contents daily in order to find food and supplies so that they can survive. Their home is really a shack that is barely held together and the surrounding "yard" has nasty old appliances and furniture and a "fence" made of broken gardening tools, etc...
In stark contrast to this, we see Mayella's geraniums. Amidst the poverty and disgusting living conditions, Mayella has managed to carve out a tiny space of beauty. Her geraniums can be said to be symbols of several different things. First, they can represent the human need for order and chaos. They can represent the fact that in spite of how outwardly ugly someone or something is, there is beauty if you look closely enough. They can also represent the fact that perhaps Lee believed that all humans are good at their core, in spite of what is on the outside.