Wild radish

Wild radish is an annual that grows up to 75 centimetres (30 in) tall, variously branched to multi-stemmed, with a distinct slender taproot which does not swell like that of the cultivated radish. The stems are green and sometimes purple at the base and nodes, round in cross section and slightly ridged, and bristly-hairy all over. It has a basal rosette of pinnate leaves to 38 cm (15 in) long, with a 3-cm stalk (petiole) and a large rounded terminal lobe that has a undulate margin; the lateral lobes sometimes overlap the midrib. The stem leaves become progressively less lobed as they ascend, and more acutely serrated. Both the upper and lower surface of each leaf is roughly hairy, as are the leaf margins, which have minutely bulbous-based hairs projecting horizontally. The leaves have green or purple tips (hydathodes) on each tooth.

The flowering period is between May and October in northern Europe, or between June and August in Minnesota. The inflorescence is a lax raceme, terminal or arising from the leaf axil, up to 34 cm long with up to 42 flowers. The flowers have four white (sometimes yellow or purple) petals, up to 24 mm long, sometimes with dark veins (especially on the underside). Each petal has a rounded "limb" above a narrow "claw", both about the same length. The four upright sepals are shorter than the petals, green or purple, and have sparse bulbous-based hairs. …

It is native to temperate regions of North Africa, Europe and parts of Western Asia.

Range. It is found in North Africa, within Macaronesia, Madeira Islands, Canary Islands, Algeria, Egypt, Libya, Morocco and Tunisia. Within Western Asia it is found in the Caucasus, Armenia, Azerbaijan, Cyprus, Georgia, Iran, Iraq, Israel, Jordan, Lebanon, Syria and Turkey. In eastern Europe, it is found within Belarus, Moldova and Ukraine. In middle Europe, it is in Austria, Belgium, Czech Republic, Germany, Hungary, Netherlands, Poland, Slovakia and Switzerland. In northern Europe, in Denmark, Estonia, Finland, Ireland, Isle of Man, Latvia, Lithuania, Norway, Sweden and United Kingdom. In southeastern Europe, within Albania, Bosnia and Herzegovina, Bulgaria, Croatia, Greece, Italy, Montenegro, North Macedonia, Romania, Serbia and Slovenia. Also in southwestern Europe, it is found in France, Portugal and Spain.

It is frost hardy, and even hard freezes only temporarily interrupt bloom. In Australia, it is regarded as a habitat threatening invasive species in many areas. In Canada, it is a naturalised species and sometimes hybridizes with cultivated radish, R. sativus. It has also proved to be resistant to several herbicides. In southeastern USA, the pale yellow form is common, sometimes entirely taking over fields in wintertime. It is a significant source of pollen and nectar for a variety of pollinators, especially honey bees during the very early spring starting buildup. Female Andrena agilissima, or mining bees, frequent this plant to obtain pollen and nectar. Other pollinators include cabbage butterflies and a few syrphid fly species.

All tender parts of the plant are edible. The leaves and flowers have a spicy taste or aftertaste. The seedpods can be eaten, as can the outer skin of the root (after being washed). It is said that John Walker cultivated sea radish root as an alternative to horseradish after discovering the plant on the west coast of Scotland as early as 1753.