It's the Great Depression and Lizabeth is a teenager who is about to approach adulthood. However, at this time she is still holding on to her childhood innocence and spirit. Along with her friends, she and Joey throw rocks at marigolds that belonged to Miss Lottie, or the "witch" as they would say.
After beheading some of Miss Lottie's flowers, Lizabeth heads home, only to overhear her father break down and her mother comfort him. This makes Lizabeth realize that everything is upside down and out of order. Blinded by her confusion, she runs to Miss Lottie's garden and rips out all the marigolds. She looks up and sees Miss Lottie, which snaps her back into reality.
A few years have passed and Lizabeth is now an adult. She reflects on the childish things that she did in the past and now realizes why Miss Lottie grew these flowers. Lizabeth has since let go of her childhood innocence and accepted the compassion that came with her age. She has now planted marigolds in her own garden.