what is the significance of the wild rosebush that grows beside the prison door

With the reference to Ann (actually Anne) Hutchinson, the prison also serves as a metaphor for the authority of the regime, which will not tolerate deviance from a prescribed set of standards, values, and morals. Hutchinson was a religious but freewheeling woman who disagreed with Puritanical teachings, and as a result she was imprisoned in Boston and then banished. She eventually was a founder of antinomian Rhode Island. Hawthorne claims that it is possible that the beautiful rosebush growing directly at the prison door sprang from her footsteps. This implies that Puritanical authoritarianism may be so rigid that it obliterates both freedom and beauty.

The rosebush itself is an obvious symbol of passion and the wilderness, and it makes its most famous reappearance later when Pearl announces that she was made not by a father and mother, or by God, but rather was plucked from the rosebush. Roses appear several times in the course of the story, always symbolizing Hester's inability to control her passion and tame it so that she can assimilate to Puritan society. Pearl too is marked by this wildness.