Rose is initially as passive and delicate as her name suggests.
She liked playing the victim role to her husband’s hero, but then her husband got tired of their roles and asked for a divorce. She refuses to take any responsibility or make any major decisions, because making decisions confuses her. She lacks wood in her character; she's a pushover.
Why on earth is Rose so averse to making decisions? It seems to date back to her brother Bing drowning when Rose was supposed to be watching him. She seems to worry about the results of her actions and whether or not she'll be blamed. She feels like there are too many options available to her, and therefore too many opportunities to make the wrong decision. In her mind, making no decision at all is better than making a bad decision.
Rose's passivity is compounded by her propensity to avoid conflict—especially with her mother. When Rose knows that her mother will try to convince her to fight for her marriage, Rose attempts to avoid her mother. When her mother calls and gives her the advice to stand up for herself, Rose just gets off the phone as quickly as possible. In their relationship, An-mei sees the problems that Rose faces and wants to help, but Rose pushes her away. She’d rather talk to a psychiatrist than her mother.
But, by the end of Rose’s story, her relationship both with her mom and her ability to stand up for herself changes. After Rose asserts herself to Ted, saying she wants to keep the house after the divorce, she dreams that her mom is helping her landscaping the garden by planting weeds. This packs a symbolic wallop: whereas Ted loved a tidy garden, Rose decides likes it overgrown abundance.
So in her dream, her mother is actually helping her to achieve her goals: to create her chaotic, ideal garden.