Nemesia caerulea is a blue- to purple- flowered herbaceous perennial member of the Plantaginaceae family. The plant is native to the Cape Floristic Province of southwestern South Africa, where it grows at low elevations on fully exposed north-facing and northwest-facing slopes in association with other native grasses and forbs. Its chromosome number is 2n=18. In temperate regions it is usually grown as an annual. The cultivar 'Sea Mist' has gained the Royal Horticultural Society's Award of Garden Merit.