Jessie, nearly 13 and Isa’s twin, acts as the logical and scientific mind of the Vanderbeeker siblings. She is a round, dynamic character who approaches the world with a need for evidence and order. Initially, she is skeptical of the garden project, dismissing the abandoned lot as uninteresting and pointing out the practical obstacles, such as the locked gate and their lack of gardening knowledge. Her scientific worldview makes her dismissive of Hyacinth’s belief that plants have feelings or that the garden is haunted, stating, “It has never been scientifically proven that ghosts actually exist” (8). Despite her initial pragmatism, her deep love for her family and neighbors, especially Mr. Jeet, overrides her hesitation. Once committed, she becomes the project’s primary planner, writing a liability waiver, creating a budget, and organizing the work.

In the absence of her twin, Isa, Jessie steps into a more prominent caretaking role for her younger siblings. While she finds their emotional displays awkward at times, she consistently provides comfort and guidance, patting her sisters’ backs after Mr. Jeet’s collapse and leading the effort to water Miss Josie’s dying seedlings. This nurturing instinct coexists with her intellectual curiosity. Though she claims botany is not one of her interests, the garden becomes a living laboratory for her. She researches, makes plans, and uses her scientific mind to solve practical problems, eventually becoming captivated by the miracle of seeds and soil. Her relationship with the returned Orlando, her former science-loving friend, reinvigorates this side of her personality and adds important expertise to the garden project.

Beneath her practical exterior, Jessie possesses a deep and quiet selflessness. Oliver’s discovery of her acceptance letter to Pecks Pond Science Camp reveals a significant secret: She declined the opportunity to spare her parents the financial burden of room and board, especially since they were already paying for Isa’s orchestra camp. By telling her family she was not accepted, she protected both their finances and Isa’s joy. This act of sacrifice highlights a maturity and empathy that underpins all her actions. Her journey is one of learning to balance her scientific mind with the emotional and rewarding work of building something beautiful with her community. The garden teaches her that some of the most important outcomes, like hope and healing, cannot be measured with scientific instruments.

Seven-year-old Hyacinth is the emotional and spiritual heart of the Vanderbeeker siblings. A round and dynamic character, she possesses a deep, intuitive empathy for people, animals, and the natural world. This connection is evident in her bond with her dog, Franz, her gentle care for Mr. Beiderman’s cat, and her belief that she can communicate with trees. Initially, she shares her siblings’ fear of the abandoned lot, believing it to be haunted. However, her unique perception allows her to see beyond the neglect. She feels the large silver maple tree, the “Silver Queen,” beckoning to her, a connection that leads her directly to the hidden, ivy-covered gate. This moment establishes her as a character guided by an instinct that transcends logic, and she is fundamental to the theme of Nature as a Unifying Force.

Hyacinth’s defining trait is her boundless compassion, which she extends to even the most difficult characters. While Oliver sees Herman as a rival, Hyacinth finds common ground with him through their shared, and surprising, interest in knitting. This connection, symbolized by the yarn they use, allows her to see the lonely boy beneath Herman’s boastful exterior, and their friendship becomes a bridge that brings Herman fully into the garden project. She is also keenly attuned to Mr. Beiderman’s grief. She understands his sadness in a way her more pragmatic siblings do not, recognizing that his healing cannot be rushed. Her gentle nature makes her a favorite of the lonely landlord, and she provides him with quiet companionship and understanding.

Throughout the story, Hyacinth acts as the group’s moral and emotional compass. While Jessie focuses on logistics and Oliver on action, Hyacinth is concerned with the feelings of those involved. Her imaginative worldview, heavily influenced by books like The Secret Garden and Anne of Green Gables, allows her to see the magical potential of the neglected lot. Her unwavering belief in the goodness of the project and the people around her helps sustain the group’s hope, even when faced with setbacks.

As the youngest Vanderbeeker at five and a quarter years old, Laney is a round character who is a catalyst for several of the narrative’s most important events. Her personality is a blend of childhood innocence, surprising determination, and a literal interpretation of the world that often leads to humorous misunderstandings. Her primary motivations are pure and direct: She loves her family, her rabbit Paganini, and her neighbors, and she wants to help them. This straightforward love drives her to commit her entire life savings of $43 to the garden project without a moment’s hesitation.

Despite Laney’s age, her actions have a deep impact on the plot. While digging for rocks, she unearths Luciana’s buried box of seeds, a discovery that proves to be the key to unlocking Mr. Beiderman’s grief and securing his help in saving the garden. Later, her frustration with the adults’ gatekeeping prompts her to smuggle Paganini into the hospital. This reckless act of love leads directly to a breakthrough for Mr. Jeet, whose laughter at the sight of the rabbit is the first sound he has made since his stroke. In these moments, Laney demonstrates that the simplest acts, when motivated by love, can create the most significant healing.

Laney’s perspective also grounds the story in the wonder of childhood. She finds joy in collecting pebbles, believes in the magical power of green M&M’s, and is convinced her pumpkin will win the contest. While her older siblings grapple with complex emotions and logistical challenges, Laney’s focus remains on the immediate and the heartfelt. Her unwavering belief in the garden and her direct, uncomplicated approach to problems often cut through the noise, reminding the other characters of the project’s simple, essential purpose: to create a place of love and healing.

Mr. Beiderman, the Vanderbeekers’ third-floor neighbor and landlord, is a deuteragonist whose journey from isolation to re-engagement is central to the narrative. As a round and dynamic character, he begins the story as a recluse who has not left his brownstone in six years, trapped by the grief of losing his wife and daughter, Luciana. Initially, he is a peripheral figure, offering gruff commentary from the sidelines. However, the children’s garden project, located on the site of his daughter’s former preschool, slowly draws him out. His first reaction to the mention of the lot is to pale and retreat, showing the painful power of the location’s memories. Yet, he cannot remain entirely detached, and he observes the children’s progress from his third-floor window, eventually throwing down high-quality gardening gloves for them in a silent act of support.

The discovery of Luciana’s buried box of seeds is the turning point for Mr. Beiderman. This symbol of his daughter’s memory, unearthed by the children, physically connects his private sorrow with their public, life-affirming project. This moment bridges his past with the present, transforming the garden into a place where his daughter’s legacy can continue to grow. This catalyst empowers him to fully join the children’s cause, giving his grief a constructive purpose.

Mr. Beiderman’s transformation culminates in a dramatic and heroic act. When the garden is threatened by developers, he breaks his six-year isolation but with purpose. He travels on the subway, confronts Mr. Huxley, and uses his research skills to prove the land’s historical significance, securing a cease-and-desist order and ensuring its preservation. His return to the world is an act of service to the community that helped him heal. He evolves from a man imprisoned by his past to a man who uses that past to protect his community’s future, embodying the novel’s core belief in the redemptive power of connection and shared purpose.

Herman begins the story as Oliver’s rival and is a foil to him. He is initially presented as a flat character, defined by his complaints and his expensive possessions, like the Eastern Racer 500 bike that Oliver covets. To Oliver, Herman represents unearned privilege and a lack of gratitude. However, the narrative gradually reveals him to be a lonely boy seeking connection. His father is emotionally distant, and his mother is often away for work, leaving him isolated. His abrasive exterior is a defense mechanism that hides a desire for friendship.

His transformation is catalyzed by his unexpected friendship with Hyacinth. Their shared passion for knitting becomes the bridge between them, allowing Herman to reveal a softer, more creative side. This connection, symbolized by the yarn they use for their “yarn bombing” project, brings him into the Vanderbeekers’ orbit in a positive way. Joining the garden project gives him a sense of purpose and belonging, and he becomes a dedicated member of the group, contributing his labor and his most prized possession. In an act of generosity, he sells his bike to buy lavender and roses for the garden, demonstrating a complete shift from materialism to community-minded selflessness. His journey shows that The Power of Community Action can reform relationships and reveal the hidden depths of a person.

Miss Josie and Mr. Jeet are the Vanderbeekers’ beloved second-floor neighbors whose crisis incites the novel’s plot. They are round, static characters who function as the heart of the brownstone community. Miss Josie is a warm, nurturing figure whose past as an educator at the New York Botanical Garden provides the initial inspiration for the garden. She is the first to suggest turning the neglected lot into a green space, planting the seed of the idea in the children’s minds. Throughout the story, she remains a source of love and stability, even while facing the trauma of her husband’s illness.

Mr. Jeet is a dapper, gentle man whose sudden stroke galvanizes the children into action. His physical well-being becomes the central goal of their project, which they conceive of as a “healing garden” for him. Oliver’s health chart, tracking Mr. Jeet’s “Good Days” and “Bad Days,” externalizes the children’s collective hope and anxiety for his recovery. Though he is physically incapacitated for much of the book, his gentle spirit remains a guiding force. His eventual recovery, marked by his laughter at seeing Paganini in the hospital, is a triumphant moment for the community that has worked so hard on his behalf. Together, Mr. Jeet and Miss Josie represent the cherished elders of the community, whose well-being is the responsibility and privilege of their neighbors to protect.

Mr. Huxley, Herman’s father and the church treasurer, is the story’s primary antagonist. He is a flat character, defined by a single-minded focus on pragmatism and finance. Motivated by the church’s need for a new boiler and other repairs, he views the abandoned lot next door as a disposable asset. His actions represent the threat of profit-driven urban development against the preservation of community spaces and historical landmarks. He is consistently dismissive and distracted, often looking at his phone while interacting with others, and his sharp, business-like demeanor contrasts with the warmth and collaborative spirit of the Vanderbeeker community.

Although physically absent for most of the narrative while at an orchestra camp, 12-year-old Isa remains a significant presence. She is Jessie’s twin and a static character, acting as a source of stability and wisdom from afar. Her siblings, particularly Jessie, feel her absence keenly and often wonder what she would advise. She stays connected through phone calls and texts, offering encouragement and a level-headed perspective on the garden project. It is Isa who suggests that making the garden beautiful is the best defense against developers, because “only a heartless grub would put a building on top of a community garden” (163). Her return at the end of the novel symbolizes the family’s reunification and the successful culmination of the summer’s challenges.