Symbolism in The Secret Garden

In the novel 'The Secret Garden,' Frances Hodgson Burnett employs various symbols to emphasize emotional growth and transformation. The garden itself is a significant symbol, representing rejuvenation and the healing power of nature. One pivotal scene depicts Mary Lennox discovering the overgrown garden, initially filled with weeds and thorns, which serves as a metaphor for her own untamed emotions and isolated life. As Mary begins to care for the garden, it flourishes, paralleling her journey from loneliness to friendship and joy. Within this context, what does the garden symbolize in Mary’s transformation?