She was born Isabel Flores y de Oliva in the city of Lima, then in the Viceroyalty of Peru, on April 20, 1586. She was one of the many children of Gaspar Flores, a harquebusier in the Imperial Spanish army, born in San Germán on the island of San Juan Bautista (now Puerto Rico), and his wife, María de Oliva, a creole from Lima. Her later nickname "Rose" comes from an incident in her babyhood: a servant claimed to have seen her face transform into a rose. In 1597 she was confirmed by the Archbishop of Lima, Turibius de Mongrovejo, who was also to be declared a saint. She formally took the name of Rose at that time.
As a young girlin emulation of the noted Dominican tertiary, St. Catherine of Sienashe began to fast three times a week and performed severe penances in secret. When she was admired for her beauty, Rose cut off her hair and smeared pepper on her face, upset that suitors were beginning to take notice of her. She rejected all suitors against the objections of her friends and her family. Despite the censure of her parents, she spent many hours contemplating the Blessed Sacrament, which she received daily, an extremely rare practice in that period. She was determined to take a vow of virginity, which was opposed by her parents, who wished her to marry. Finally, out of frustration, her father gave her a room to herself in the family home.
After daily fasting, she took to permanently abstain from eating meat. She helped the sick and hungry around her community, bringing them to her room and taking care of them. Rose sold her fine needlework, and took flowers that she grew to market, to help her family. She made and sold lace and embroidery to care for the poor, and she prayed and did penance in a little grotto which she had built. Otherwise, she became a recluse, leaving her room only for her visits to church.
She attracted the attention of the friars of the Dominican Order. She wanted to become a nun, but her father forbade it, so she instead entered the Third Order of St. Dominic while living in her parents' home. In her twentieth year she donned the habit of a tertiary and took a vow of perpetual virginity. She only allowed herself to sleep two hours a night at most, so that she had more hours to devote to prayer. She donned a heavy crown made of silver, with small spikes on the inside, in emulation of the Crown of Thorns worn by Christ.
For eleven years she lived this way, with intervals of ecstasy, and eventually died on August 24, 1617, at the young age of 31. It is said that she prophesied the date of her death. Her funeral was held in the cathedral, attended by all the public authorities of Lima.