Part of the reason that both Colin and Mary are in such poor states when the reader meets them is because none of their living parents actually wanted them. The officers that rescue the forgotten Mary out of her parents' home after devastating a cholera outbreak note that they didn't even know that Mary's mother had a child, while following the death of Mrs. Craven, Mr. Craven couldn't bear to look at his son and therefore removed himself from Colin's life altogether. While the novel squarely blames the parents and the people the parents put in charge of their children for Colin and Mary's poor health and attitudes, it also makes the case that an essential cure for the children's ills is friendship with people their own age, rather than installing other adult authority figures who, the novel suggests, would be unable to empathize with the children and meet them where they are.
Both Mary and Colin have been raised almost exclusively by hired help, not by their parents. While the novel doesn't vilify hired help across the board (Martha, Mary's maid at Misselthwaite, is a huge contributor in many ways to Mary and Colin's friendship, as well as to Mary's discovery of the power of nature), it does suggest that certain types of people who are hired to raise children can actually have lasting ill effects on them. Because of Mary and Colin's statuses as well-to-do young people, the people who raise them, such as Mary's Ayah and Colin's nurse, have little power to punish or reprimand their charges. Instead, when Mary and Colin get angry, there's nothing stopping them from slapping their caregivers and forcing those women to let the children have their way. While it's easy to see this as a consequence of spoiling the children or simply not allowing the adults to do their jobs, the ways in which the children begin to change their habits when they meet each other suggests that the true issue is that both Mary and Colin are lonely and crave either attention from their birth parents or friendship with a peer. Within the world of the novel, an adult hired in the capacity of a nurse or a governess isn't capable of giving Mary or Colin what they actually need: love, empathy, and an equally strong selfish nature to act as a mirror and encourage better behavior.
On the night of Colin's final tantrum, Mary learns that Colin is so caught up in his own self-importance and misery that he can spin the whole household into a terrified flurry by crying, screaming, and throwing a massive fit. Furthermore, because Mr. Craven doesn't concern himself with his son's antics, and because the caregivers must do as Colin says, this behavior is allowed to continue. While Colin's screams scare Mary as they do the rest of the household, her own selfishness gives her the courage to bluntly confront Colin, tell him he's being silly and self-involved, and shame him into calming down. Notably, as Mary and Colin's friendship grows, the fact that they were both raised to think only of themselves allows them to check the other when they behave selfishly. As with their fight, Mary is able to confront Colin at several points exactly because it never occurs to her to consider Colin's feelings, and Mary is also able to observe that when she does behave kindly to others, they in turn treat her better. On the other hand, when Mary makes friends with the robin, Ben Weatherstaff, and Dickon and his creatures, she's able to befriend them in part because she recognizes her own lower status in relation to them. Ben Weatherstaff, as a cantankerous adult, has no qualms about hurting Mary's feelings, while the robin and Dickon both show Mary through their actions that if she wants to be around them, she has to behave in ways that make them comfortable.
It's only after Colin and Mary have put these checks and balances on each other and through doing so, learn to think about people other than themselves that they're able to accept parental guidance or, in Colin's case, decide he wants it at all. They test this through their relationship with Susan Sowerby, Martha and Dickon's mother. Mary is entranced by the idea of Mrs. Sowerby from the minute that Martha starts talking about her (and for much of the novel, even mimics Martha by referring to Mrs. Sowerby just as "mother"). After Mary and Colin become more and more empathetic and curious about Mrs. Sowerby's life, Mrs. Sowerby comes to visit them in the secret garden and, through her embraces, kind manner, and genuine interest, shows them what a kind and loving parent figure is like. This process culminates in Colin coming to terms with the death of his own mother and his desire to make his father proud. The empathy he develops over the months he spends in the secret garden allows him to think of the portrait of his mother in his bedroom as smiling down on him, while wanting to make Mr. Craven proud to have a son guides Colin's every choice and action. Importantly, Mrs. Sowerby is also responsible for Mary's ability to run free around Misselthwaite—she's in regular contact with Mr. Craven's household staff and advocates for Mary to be allowed outside for another few years before receiving a governess.
While there's no chance for Mary to ever have a positive relationship with her late parents, the novel's ending—in which Mr. Craven and Colin affirm their relationship and their affection for each other, while Mary and Colin have become kind, thoughtful and empathetic individuals through their experiences with each other and working in the secret garden—leaves the children in a place in which they finally have the emotional skills to grow up and move forward into adulthood.
Childrearing and Friendship ThemeTracker
Childrearing and Friendship Quotes in The Secret Garden
Mary had never possessed an animal pet of her own and had always thought she should like no one. So she began to feel a slight interest in Dickon, and as she had never before been interested in any one but herself, it was the dawning of a healthy sentiment.
"A bird with a red breast was sitting on one of them and he sang."
To her surprise the surly old weather-beaten face actually changed its expression. A slow smile spread over it and the gardener looked quite different. It made her think that it was curious how much nicer a person looked when he smiled. She had not thought of it before.
"I wonder," staring at her reflectively, "what Dickon would think of thee?"
"He wouldn't like me," said Mary in her stiff, cold little way. "No one does."
Martha looked reflective again.
"How does tha' like thysel'?" she inquired, really quite as if she were curious to know.
"Not at all—really," she answered. "But I never thought of that before."
She walked away, slowly thinking. She had begun to like the garden just as she had begun to like the robin and Dickon and Martha's mother. She was beginning to like Martha, too. This seemed a good many people to like—when you were not used to liking.
"Martha," she said, "they were your wages. It was your twopence really. Thank you." She said it stiffly because she was not used to thanking people or noticing that they did things for her. "Thank you," she said, and held out her hand because she did not know what else to do.
"Do you like roses?" she said.
Ben Weatherstaff rooted up a weed and threw it aside before he answered.
"Well, yes, I do. I was learned that by a young lady I was gardener to. She had a lot in a place she was fond of, an' she loved 'em like they was children—or robins. I've seen her bend over an' kiss 'em." He dragged out another weed and scowled at it. "That were as much as ten year' ago."
"Could you keep a secret, if I told you one? It's a great secret. I don't know what I should do if any one found it out. I believe I should die!" She said the last sentence quite fiercely.
Then Mary did a strange thing. She learned forward and asked him a question she had never dreamed of asking any one before. And she tried to ask it in Yorkshire because that was his language, and in India a native was always pleased if you knew his speech.
"Does tha' like me?" she said.
"Oh, what a queer house this is!" Mary said. "What a queer house! Everything is a kind of secret. Rooms are locked up and gardens are locked up—and you! Have you been locked up?"
"Oh, don't you see how much nicer it would be if it was a secret?"
He dropped back on his pillow and lay there with an odd expression on his face.
"I never had a secret," he said, "except that one about not living to grow up. They don't know I know that, so it is a sort of secret. But I like this kind better."
And they both began to laugh over nothings as children will when they are happy together. And they laughed so that in the end they were making as much noise as if they had been two ordinary healthy natural ten-year-old creatures—instead of a hard, little, unloving girl and a sickly boy who believed that he was going to die.
"He's been lying in his room so long and he's always been so afraid of his back that it has made him queer," said Mary. "He knows a good many things out of books but he doesn't know anything else. He says he has been to ill to notice things and he hates going out of doors and hates gardens and gardeners. But he likes to hear about this garden because it is a secret."
Mary's lips pinched themselves together. She was no more used to considering other people than Colin was and she saw no reason why an ill-tempered boy should interfere with the thing she liked best. She knew nothing about the pitifulness of people who had been ill and nervous and who did not know that they could control their tempers and need not make other people ill and nervous, too.
[…] If he had had childish companions and had not lain on his back in the huge closed house, breathing an atmosphere heavy with the fears of people who were most of them ignorant and tired of him, he would have found out that most of his fright and illness was created by himself. But he had lain and thought of himself and his aches and weariness for hours and days and months and years. And now that an angry unsympathetic little girl insisted obstinately that he was not as ill as he thought he was he actually felt as if she might be speaking the truth.
The scene which Dr. Craven beheld when he entered his patient's room was indeed rather astonishing to him. As Mrs. Medlock opened the door he heard laughing and chattering. Colin was on his sofa in his dressing-gown and he was sitting up quite straight looking at a picture in one of the garden books and talking to the plain child who at that moment could scarcely be called plain at all because her face was so glowing with enjoyment.
Colin flushed triumphantly. He had made himself believe that he was going to get well, which was really more than half the battle, if he had been aware of it. And the thought which stimulated him more than any other was this imagining what his father would look like when he saw that he had a son who was as straight and strong as other fathers' sons.
"You are just what I—what I wanted," he said. "I wish you were my mother—as well as Dickon's!"
All at once Susan Sowerby bent down and drew him with her warm arms close against the bosom under the blue cloak—as if he had been Dickon's brother. The quick mist swept over her eyes.
"Eh! Dear lad!" she said. "Thy own mother's in this 'ere very garden, I do believe. She couldna' keep out of it. Thy father mun come back to thee—he mun!"