Why are the marigolds so important to Miss Lottie, and why do the children hate them?

The marigolds are important to Miss Lottie because they symbolize hope and beauty in the face of adversity. The children hate the marigolds because they feel they don't fit in..... because their beauty only accentuates the ugliness in their lives.

For some perverse reason, we children hated those marigolds. They interfered with the perfect ugliness of the place; they were too beautiful; they said too much that we could not understand; they did not make sense.