As the novel’s title suggests, the weedflower (also referred to as kusabana and stock) has particular significance to Sumiko. It symbolizes Sumiko’s resilient and unique personality. Sumiko stands out from the other girls her age; she loves the scent of dirt and doesn’t mind hard work. Helping on Auntie and Uncle’s farm is more than a requirement; it’s something she enjoys. Even her dream to own a flower shop someday revolves around flowers. In the camp, growing stock gives her a purpose and keeps her from going crazy with boredom. Like Sumiko, the weedflower stands out from others. It has a particular scent (which Sumiko loves) and flourishes even in the hot desert sun. Although other people don’t see stock as a desirable or valuable flower, Sumiko singles it out as her favorite.

Kadohata draws a connection between Sumiko and the weedflower not only in Sumiko’s love of the flower but also through Frank’s perceptions of her. Frank calls Sumiko “Weedflower” as a nickname, so consistently that his older brother thinks it’s her given name. When Franks sees Sumiko’s weedflowers growing at the camp, he tells her that the stock looks like Sumiko.