The Bean Trees takes place in rural Pittman County, Kentucky, during the 1980s. Its narrator, Taylor Greer, begins the story with anecdotes concerning her childhood and later her teenage years. As a child, she remembers watching a tractor tire blow up and send Newt Hardbine's father flying over the top of the Standard Oil sign, and has always been afraid of tires. Taylor's original name was Marietta Greer, but at three years old she demanded to be called Miss Marietta, and this name eventually became Missy. (The narrator will choose to call herself Taylor at the end of the first chapter).
By high school, Taylor is not an exemplary student but stays out of trouble. In her senior year, she has the blond, northerner Hughes Walter as her science teacher, and when he tells his students about a job possibility at the hospital where his wife works. Although believing that Hughes Walter will offer the job to a Candy Striper, Taylor gets the job when she is the only one to inquire about it. While working at the hospital, during her first week Newt Hardbine and his wife, Jolene Shanks, are brought in after an accident: during a fight with Newt's father, both Newt and Jolene are shot, and Newt is dead. Taylor must comfort Jolene, and she asks her why she married Newt. Jolene answers "why the hell not," since she had been called a slut by her father since she was thirteen.
Despite this traumatic experience, Taylor does not quit the hospital and even stays on for over five years as she saves her money. She buys Volkswagen bug with no windows and no starter, and decides to leave Pittman County. On the way, she makes two promises: to go as far west as possible until her car stops, and to choose a new name. It is here that she chooses the name Taylor.
While in Oklahoma, Taylor's steering wheel stops working, and she must stop in the middle of a Cherokee reservation. A mechanic named Bob Two Two fixes her car and overcharges her. While staying at the town on the Indian reservation, Taylor stops at a diner to eat, and can only afford a ninety-nine cent cheeseburger. Upon leaving the diner, an Indian woman who was there with two men follows Taylor and insists that she take her child. Taylor relents, claiming that she can't take the baby because she doesn't have the papers, but the woman says that nobody knows or cares that the baby is alive. Taylor finally takes the child, and they arrive at a hotel where Taylor must beg for a room. When she bathes the child, Taylor realizes that the baby girl has bruises and worse.
After the first chapter, the narrative shifts to Tucson, Arizona, and adopts a third person narration in dealing with the story of Lou Ann Ruiz, whose husband, Angel, had left her on Halloween while she is pregnant with her first son. Lou Ann learned this when she returns from errands. She first visits her gynecologist, Dr. Pelinowsky, and then Lee Sing market, where the elderly Chinese owner of the market, Lee Sing, remarks that, if Lou Ann has a girl, it will be like "feeding the neighbor's New Year pig. All that work. In the end, it goes to some other family." When she returns home, she realizes that Angel has left.
In the third chapter, Taylor and the Indian girl, which she names Turtle, remain at the Broken Arrow hotel and make money by changing beds for the owner, Mrs. Hoge. Taylor and Turtle arrive in Tucson during a hailstorm, and the car breaks down once more. They take cover at a building where a man questions Taylor, so she drives her car a bit farther to Jesus Is Lord Used Tires. A woman named Mattie helps Taylor with her car, and helps Taylor with Turtle, warning her against dehydration and giving her peanut butter crackers. Taylor notices a priest enter; there is a family of Indians in the back of his station wagon. When Taylor compliments Mattie on her parenting instincts and says she must have grandchildren, Mattie says that she has "something like that."
Taylor and Turtle stay in the nearby Hotel Republic, and Taylor enjoys the new sights and excitement of the more developed Tucson. Although she applies for a job at a blood bank, she cannot work there if she is not a licensed phlebotomist. Instead, she becomes friends with Sandi, the waitress at the nearby Burger Derby. Sandi, herself a single mother, is crazy about horses and pries Taylor for information about them because she lived in Kentucky. Taylor says that Turtle is not really hers, but "somebody I got stuck with," and Sandi knowingly replies that she knows "exactly what you mean."
The fourth chapter is the second and final time that Kingsolver abandons Taylor's narration to tell the story of Lou Ann Ruiz. Her mother, Ivy, and her grandmother, Granny Logan, have been staying with her since the birth of her son, Dwayne Ray. In order to avoid conflict, Angel had moved back in so that neither Ivy nor her mother would know about the impending divorce. Granny Logan suggests that Lou Ann move in with them back in Kentucky, but Lou Ann lies and says that, because of her husband, she cannot leave. Granny Logan brought water from Tug Fork, Kentucky, to baptize Dwayne Ray, even though Lou Ann and Angel had already decided to give him a Catholic baptism. After Ivy and her mother leave, Angel returns and asks whether he has seen several of his possessions. He pours the water from Tug Fork down the drain.
The fifth chapter returns to Taylor's first person narration, and the novel will remain at this perspective for its remainder. Taylor works at the Burger Derby for six days before quitting after a fight with the manager. She attempts to look for a place to stay, and finds two ads in the paper: one reads "Must be open to new ideas," while the other reads "New mom needs company. Own room, low rent, promise I won't bother you. Kids okay." Taylor visits the house for the first ad, and meets Fei, La-Isha and Timothy. Fei apologizes for Timothy, for he consumed caffeine and now "his homeostasis is out of balance," and reprimands him for asking Turtle's gender, for gender is not an issue. Fei also says that straining curd as part of a soy-milk collective is a house requirement. Taylor next visits the house for the second ad: it belongs to Lou Ann Ruiz, and the two Kentucky natives are soon joking about the soy milk collective. Lou Ann offers Taylor the room, and she readily accepts.
Despite her great fear of tires, Taylor takes a job at Jesus Is Lord Used Tires. At the tire shop, Taylor learns that Mattie runs a sanctuary for refugees. Father William, the priest whom she met on her first visit to the shop, helps Mattie with the refugees. Eventually, Taylor admits to Mattie her fear of exploding tires, and Mattie solves this problem by throwing a twenty-five pound container of water at her. She claims that this is the weight of the air in a tire, and the damage that Taylor suffered (she got the wind knocked out of her) is the worst she could ever suffer from the small tires in the shop.
Taylor learns that Lou Ann views life as if anything can be a life-threatening experience, and eventually she insists that Lou Ann not help her so much, for they are beginning to act like a married couple. To settle this argument, they begin drinking, and Lou Ann frets about becoming drunk, for she fears that she might say something to ruin their friendship. Taylor gives Lou Ann her opinion on men: it is like the products used for toilet repair: parts are included for all installations, but no installation requires all parts. Taylor believes that no man could use all of her parts.
Taylor, Lou Ann and Mattie go on a picnic with two Guatemalan refugees, a married couple named Estevan and Esperanza. While Estevan is merely compact, Esperanza seems shrunken and incredibly damaged. She cannot take her eyes off of Turtle, and when Taylor asks Estevan about this, he replies that Turtle reminds her of a child that Esperanza knew in Guatemala. On the way back from the picnic, Estevan suddenly stops Mattie's car. Taylor, who is driving behind them, must immediately stop her car as well. When this happens, Turtle does a somersault and then makes her first noise, a laugh. Taylor learns that Estevan stopped in order to avoid hitting a bird on the road.
Turtle soon says her first word: bean. One night, Lou Ann and Taylor invite Esperanza and Estevan over for dinner, as well as their neighbors, Edna Poppy and Virgie Mae Parsons. Virgie Mae thinks that Turtle is Esperanza's and Estevan's child, for she looks like a "little wild Indian," but Taylor says that she is a wild Indian, but is hers. During the dinner, Virgie laments the influx of immigrants in the United States, and Taylor barely contains her contempt. Estevan diffuses the situation by telling Turtle a wild Indian story about heaven and hell: in heaven and hell there are identical dinner tables, but in hell one can only jibber and jabber and not eat, while in heaven everyone eats until they are happy and fat. Taylor and Lou Ann had invited everyone over to watch Mattie on television: she is interviewed because of her work with refugees, and speaks about a "legal obligation to take in people whose lives are in danger."
Taylor learns that her mother will be married to Harland Elleston, who runs El-Jay's Paint and Body. Although Taylor resists the idea, Lou Ann assures her that she is doing the right thing. Lou Ann shows Taylor the wisteria vines that come alive in the spring in Roosevelt Park (nicknamed "Dead Grass Park" and "Dog Doo Park"), and she considers the wisteria vines blooming in barren soil to be the "Miracle of Dog Doo Park." Lou Ann learns from Virgie Mae Parsons that her husband was looking for her, and Taylor asks her whether she would accept her husband back. Lou Ann admits that she would.
Taylor apologizes to Estevan for Virgie Mae's comments during dinner, but he simply believes that this is how Americans think. When Lou Ann talks to Angel, she learns that he is leaving for good. Taylor does not see this, for when Angel returns she is at Dr. Pelinowsky's office, where she tells the doctor that she believes Turtle was molested. Dr. P diagnoses Turtle with a "failure to thrive," for sometimes in an environment of deprivation a child will stop growing. Upon returning home from the doctor, Lou Ann tells Taylor that Angel is leaving to be a one-legged clown in a rodeo. Lou Ann and Taylor realize that Turtle's name is actually April when she responds to the world, and decide that Turtle is good enough for a nickname, but she should actually be called April.
Taylor learns from Estevan that Esperanza attempted suicide by taking a bottle of baby aspiring, and had to be taken to a clinic in Tucson where she would not have to show legal documentation. Taylor attempts to talk to Estevan about his wife, and he tells her about the torture they faced in Guatemala, as well as her history there. They had a daughter named Ismene who was taken by the authorities; since Esperanza knew the names of twenty teachers' union members, the police used Ismene as a bargaining tactic. If she told the names, she would receive her daughter back. Esperanza did not tell, and thus Ismene was given to a foster family. Taylor and Estevan also discuss the class system that exists in America, and she claims that in Kentucky she was part of the lowest social order, the "Nutters," because she and her fellow students would pick walnuts to earn money for school clothes.
Lou Ann begins a job search, but refuses to settle for a job at a convenience store in a high-crime area. Taylor and Lou Ann realize that Edna Poppy is blind when she sees her at the market, and this explains Virgie Mae's role as her caretaker. Taylor visits Esperanza and attempts to comfort her, but can only tell her not to give up hope and that Estevan is crazy about her.
Lou Ann explains to Taylor why she is so neurotic. She had a dream in which an angel told her that her child would not live to see the year two-thousand. Nevertheless, her neuroses become more subdued once Lou Ann takes a job at Red Hot Mama's salsa factory, a job that Lou Ann wholeheartedly enjoys. She even rejects Angel's proposal for reconciliation when he invites her to join him on a ranch in Montana.
Mattie tells Taylor that there is trouble for Esperanza and Estevan, and they must be moved to a safe house farther from the border. In order to qualify for asylum, Esperanza and Estevan would need documentation proving that their lives were in danger when they left Guatemala.
In the middle of July, on the Native American New Year's Day, Mattie and Taylor go with Esperanza and Estevan to the desert during a storm to watch the smoky columns and rays of sunlight. When they return home, Lou Ann tells her that there was a problem with Turtle. Edna had taken Turtle to the park, and there she heard a sound. A man had accosted Turtle and may have attempted to kidnap or molest her. The blind Edna Poppy only wards the man off when she hits him with her purse. A social worker arrives with the police just as Taylor attempts to deal with the chaos of a bird that flies into the house.
Although there is no evidence that Turtle has been molested, Turtle becomes catatonic once more and Taylor begins angry at the world. She laments the lack of compassion in the world and the evil in there, but Lou Ann reassures her that she doesn't need to feel like the Lone Ranger.
Turtle proves resilient and returns from her catatonia, but Taylor remains depressed and realizes how futile her talk with Esperanza was. She also receives the bad news that she has no legal claim on Turtle and must establish this claim or else Turtle will become the ward of the state. Lou Ann demands that Taylor fight for Turtle, but she apperas ready to give up the fight. Eventually Taylor decides that she can attempt to find Turtle's parents to establish proof of abandonment. She makes an appointment with Cynthia, the social worker, and finds how she can establish custody in this way. Cynthia tells her that she has no doubt that Taylor is the best parent for Turtle, and gives her the name and address of a man dealing with public notaries in Oklahoma: Mr. Jonas Wilford Armistead.
Taylor decides that she will go to Oklahoma to find Turtle's parents, and that she will take Esperanza and Estevan to a safe house during her journey. Although Mattie warns Taylor of the dangers, she tells Mattie that there are more important things to consider. Before Taylor leaves, Edna and Virgie Mae bring over a night-blooming cereus, which opens its flower for only one night of the year. Lou Ann considers this a good harbinger for the journey.
On the journey out of New Mexico, Immigration stops Taylor's car to question them. When asked to whom Turtle belongs, Estevan quickly says that she belongs to him and his wife. Estevan later tells Taylor that he is a Mayan and chose a Spanish name when he moved to the city; he and Esperanza choose new names for living in Oklahoma: Steven and Hope. Estevan and Taylor muse about the status of illegal immigrants, wondering how a person could be "illegal." When they reach Oklahoma, Taylor finds that everything is different. At the Broken Arrow Motor Lodge, Mrs. Hoge had died and her daughter-in-law had lost over one hundred pounds.
When Taylor finds the diner where Turtle was abandoned, she realizes that everything has changed. All of the signs she remembered are gone, and a waitress tells her that the diner is under new ownership. Even Bob Two Two's garage has been shut down. Taylor feels that she is on a snipe hunt,' searching for something that does not exist, but she decides to go with Esperanza and Estevan to the nearby Lake o' the Cherokees.
At the Lake o' the Cherokees, Esperanza and Estevan seem more relaxed and comfortable, and Esperanza grows even closer to Turtle. While they pass by a cemetery, Turtle cries out "Mama," and Taylor eventually realizes that Turtle buries her dolls to replicate the burial of her mother in a cemetery. The four find a cottage and enjoy their brief vacation. Taylor and Estevan get a boat, but since neither can swim Esperanza and Turtle stay ashore. While on the boat, Estevan takes his shirt off and suns himself, and Taylor wishes to know how his chest would feel against her face, so she looks away and merely tells him how much she will miss him.
Taylor drops off Estevan and Esperanza at the Pottawatomie Presbyterian Church of St. Michael and All Angels. Estevan explains to Taylor that in the notary office, Esperanza had her chance to say goodbye to Ismene, and claims that he may return to Guatemala when the world is different. Taylor calls her Mama from Oklahoma City and bursts into tears, realizing that she has lost a man she loved but had no claim upon, but her Mama claims that if she can find love at her age and feel like a teenager again, then there is hope for anybody. She also tells about how her former employers now treat her with respect. Taylor tells Mama that Turtle is now legally her daughter.
Turtle and Taylor remain in Oklahoma City while the adoption paperwork clears, and spend time at the library. They learn about the wisteria vines. They do not grow from barren soil; the soil beneath them is fertilized by rhizobia, microscopic bugs with which the wisteria have a symbiotic relationship. Taylor compares the wisteria and rhizobia to the various relationships in the novel.
Taylor calls Lou Ann, who tells her that she is now dating a man from Red Hot Mama's, Cameron John, and she recalls how Taylor became upset when they were acting like a family. Lou Ann insists that they are in fact a family, and Taylor agrees. Taylor and Turtle head back to Tucson as a legally established family.
