Major themes in The Bean Trees include the importance of family and the need for community as emotional support systems for individuals facing hardships. Kingsolver uses her feminist beliefs, her interest in political issues, and her background in biology as vehicles to relate her thematic messages.
Throughout the novel, Kingsolver focuses on family as a major theme. Taylor ends up with Turtle, and together they form a family. When they move in with Lou Ann and her son, their family grows. Neither Taylor nor Lou Ann can afford much; by sharing expenses, they help each other survive difficult times. Lou Ann considers Taylor and Turtle family because they'd "been through hell and high water together" and because they know "each other's good and bad sides, stuff nobody else knows." Taylor and Lou Ann develop an enduring friendship and love for one another. Out of this sense of belonging and acceptance comes the notion of family, of unasked-for and freely given emotional and psychological support.
Other nontraditional families include Edna and Virgie Mae, as well as Mattie and her house full of political refugees. Because Edna is blind, she is dependent on Virgie Mae. They support and care for one another. Mattie, when asked if she has "grandbabies," responds, "Something like that." She loves the people who are in sanctuary in her house. They are fellow human beings, and she risks her life for them time and time again. What she does to care for and support these refugees is no different from what most biological family members do for each other.
Kingsolver's belief in community as a necessary support for individuals, as well as for American society, is another major theme. After Taylor and Turtle rent a room at the Hotel Republic and all of Taylor's money is spent, Taylor knows that she has to get a job; however, she finds herself in a situation too familiar to many single mothers: wondering how she will be able to afford childcare for Turtle. She feels guilty leaving Turtle at Kid Central Station in the mall and knows that she needs other resources. After Taylor moves in with Lou Ann, she finds a place where she belongs — a community, and resources within that community. She finds that she can depend on Lou Ann and her neighbors Edna and Virgie Mae to help care for Turtle. Even Mattie doesn't mind having Turtle in the Jesus Is Lord Used Tires shop while Taylor is working.
Estevan and Esperanza also become Taylor's friends and members of her community. They are people she depends on who also depend on her. Taylor takes a risk by driving them to Oklahoma to a safe house; in return, they risk their lives to save Turtle from becoming a ward of the state.
The willingness of people in a community to allow others to depend on them creates trust and a sense of belonging for both the providers and the receivers of that dependence. Community members look out for each other and support each other. In so doing, they allow all members to grow emotionally and to lead more productive lives without the worry of everyday personal security, including the need for food. Kingsolver portrays this interdependency between the community members symbolically in the symbiotic relationship between the wisteria vines and the rhizobia.
Exposing her readers to the value of community and family, Kingsolver's hope is to spur them to action, thereby making the world a kinder — and more secure — place in which to live.