Wild Radish or Jointed Charlock, Raphanus raphanistrum, is a flowering plant in the family Brassicaceae. It is sometimes claimed to be the ancestor of the edible radish, Raphanus sativus. Native to Asia (or, according to some authorities, the Mediterranean), it has been introduced into most parts of the world, and is regarded as a damagingly invasive species in many, for example Australia. It spreads rapidly, and is often found growing on roadsides or in other places where the ground has been disturbed.
In southeastern USA, the pale yellow form is common, sometimes entirely taking over fields in wintertime. It is often erroneously referred to as mustard. It is a significant source of pollen for a variety of pollinators, especially honey bees during winter. It is frost hardy, and even hard freezes only temporarily interrupt bloom.
Wild radish grows as an annual or biennial plant, with attractive four-petalled flowers 15-20 mm across and varying in colour, usually from white to purple but sometimes yellow, often with colour shading within a single petal. It flowers in early spring to late summer. Its flowers are very similar to those of the searocket, and it is found in some of the same regions, but it is easily distinguished by its thinner and non-succulent stems and leaves. It has a single taproot which is similar to that of the cultivated radish but less enlarged.