Phylum: Magnoliophyta - Class: Equisetopsida - Order: Brassicales - Family: Brassicaceae
Horseradish is not native to Britain and Ireland but it is now widely naturalised here, having been introduced sometime during the fifteenth or sixteenth century.
Horseradish grows to a height of 70cm. This stout, hairless perennial plant has a long broad tap root. The large basal leaves are oblong -lanceolate, toothed and usually held fairly erect. The much smaller stem leaves have short stalks.
Flowers, each with four white rounded petals, are typically 8 to 9 mm across and are borne in broad panicles.
Horseradish is commonly seen on roadside verges, in wasteland and on the banks of rivers and streams.
Found throughout thr UK, but less commonly in Scotland and Northern Ireland, Horseradish is thought to be native to parts of eastern Europe and western Asia, but because of its culinary value it has been introduced to most clountries with temperate climates.
Horseradish sauce is made from the thick tap roots of this plant combined with crème fraîche, vinegar and mustard; it is often served with roast beef, but it is also used with some fish dishes. Medicinal use of this plant dates back thousands of years.
The specific epithet rusticana comes from Latin and means rustic (of the countryside).
Related white-flowered brassicaceae species such as Watercress and Common Scurvey-grass have flowers of very similar appearance to those of Horseradish, but the large upright basal leaves of Horseradish are very distinctive and should avoid such confusion.