This one's Symbolism 101, folks. Violet is named for a flower, which Finch views as a symbol of life and hope. And he's not alone: Flowers are a pretty universal symbol of renewal and rebirth. Think of Japanese cherry blossom festivals, Burns' poem "A Red, Red Rose," or the abundance of flowers at weddings.
One day, during a manic episode, Finch goes to great lengths to bring her a bouquet from a greenhouse. He tells the people who run the greenhouse:
"Winter is here, and I don't know where I'll be by spring. I want her to know that I'm thinking of her and that this isn't a season of death but one for living." (40.52)
When he brings the flowers to Violet, she gets it right away. "Finch, you brought me spring," she says (40.78).
After Finch disappears, but before his body is found, Violet and her parents go to visit the site where Eleanor died:
Embedded in the ground is a license plate, one that suddenly looks familiar, and circling this is a small garden where someone has plated flowers. Finch. (51.1)
Cue the soaring music. We think that a good tagline for this book would be: Even in death, Finch is bringing her spring.