Gillyflower is a common name for Matthiola incana, a plant in the family Brassicaceae (formerly Cruciferae), now more widely known as stock, garden stock or hoary stock, etc.
It is a popular garden flower, which comes in many colors (pink, white or near-white, lavender, yellow…), plain or variegated. Gillyflowers are often used in flowerbeds along paths and alleys, where passers-by can enjoy their pleasant and sweet scent. They can also be grown for cut flowers.
Gillyflowers usually reach a height of about 12 in. (0.30 m) to about 18 in. (0.45 m), although some cultivars can grow up to 28 in. (0.70 m) or more.