It is an herbaceous biennial plant growing from a deeply growing, thin, whitish taproot scented like horseradish. In their first years, plants are rosettes of green leaves close to the ground; these rosettes remain green through the winter and develop into mature flowering plants the following spring. Second-year plants often grow from tall, rarely to tall. The leaves are stalked, triangular through heart shaped, long (of which about half being the petiole) and broad, with coarsely toothed margins. The flowers are produced in spring and summer in small clusters. Each small flower has four white petals long and broad, arranged in a cross shape. The fruit is an erect, slender, four-sided capsule long, called a silique, green maturing to pale grey brown, containing two rows of small shiny black seeds which are released when a silique splits open. A single plant can produce hundreds of seeds, which often scatter several meters from the parent plant.