Mertensia is a genus of flowering plants in the family Boraginaceae. They are perennial herbaceous plants with blue or sometimes white flowers that open from pink-tinged buds. Such a change in flower color is common in Boraginaceae and is caused by an increase of pH in the flower tissue. Mertensia is one of several plants that are commonly called "bluebell". In spite of their common name, the flowers are usually salverform (trumpet-shaped) rather than campanulate (bell-shaped).