Sumiko is a 12-year-old Japanese American girl living with her extended family following the death of her parents in a car accident. She takes her responsibilities on the family flower farm seriously, particularly her job grading carnations and tending to the stock flowers, which she calls "weedflowers." Despite her strong work ethic and deep love for the farm, she feels lonely as the only Japanese girl in her school class. She dreams of one day opening her own flower shop.

Frank is a Mohave boy living on the reservation where the Poston internment camp is built. He lacks electricity and running water in his home, making him resentful of the amenities provided to the Japanese Americans. He is curious about the new arrivals but also harbors frustration regarding their presence on his people's land. He deeply respects his older brothers and cares about the future agricultural potential of the reservation.

Bull is Sumiko's 19-year-old cousin. He is stocky, physically strong, and entirely dedicated to the family's flower farm, paying little attention to his unruly hair or clothing. He acts as a calming presence in the household, embracing the Japanese philosophy of accepting hardship. He desires to demonstrate his loyalty to the United States despite the government's racist policies.

Ichiro is Sumiko's 23-year-old cousin. He is tall, graceful, and cares significantly about his appearance, frequently styling his hair in front of the mirror and spending money on nice clothes. As the family's primary source of news from the outside world, he expresses deep anger and frustration regarding the unjust treatment Japanese Americans face.

Tak-Tak is Sumiko's younger brother. Having been a baby when their parents died, he relies heavily on his sister and extended family for a sense of security. He wears glasses, keeps pet crickets, and frequently voices the underlying fears about the war that the adults in the family attempt to hide from the children.

Jiichan is Sumiko's grandfather and a first-generation Japanese immigrant. He speaks with broken English, wears a permanent scowl that hides his humorous nature, and holds a position of profound respect in the household. His status as an immigrant places him at immediate risk of arrest by the FBI when the war begins.

Auntie is Sumiko's strict, authoritative aunt who took her in after her parents died. She holds the family to high standards and rarely shows outward affection. The sudden changes brought by the war, combined with her husband's arrest, severely challenge her usual industrious nature and temporarily leave her paralyzed by lethargy in the camp.

Uncle is a jovial man in his late forties who married into the flower farm. He is deeply passionate about cultivating flowers, constantly working to develop new strains of carnation seeds. He treats Sumiko with immense kindness and spends his own money to ensure she feels included in American social life.

Mr. Moto is an elderly Japanese American man who becomes Sumiko's neighbor in the internment camp. He lost an eye in a childhood accident but maintains a positive, accepting attitude toward his hardships. Lacking agricultural experience, he seeks Sumiko's help to start a garden in the desert dirt.

Sachi is a young Japanese American girl whom Sumiko meets in the Poston internment camp. She is highly independent, roams freely without parental supervision, and has a habit of telling wild, exaggerated lies about her background to anyone who will listen.

Joseph is Frank's older brother, a Native American youth living on the reservation. He recognizes the advanced agricultural skills of the Japanese Americans and hopes to learn farming techniques, specifically regarding irrigation, to improve his own people's land utilization after the war.

Marsha is a popular sixth-grade classmate of Sumiko's in California. She invites her entire class to her birthday party, unknowingly setting the stage for Sumiko to experience acute racial exclusion at the hands of the adult hosts.