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Definition: horseradish from The Hutchinson Unabridged Encyclopedia with Atlas and Weather Guide

Hardy perennial plant, native to southeastern Europe but naturalized elsewhere. The thick cream-coloured root is strong-tasting and is often made into a savoury sauce to accompany food. (Armoracia rusticana, family Cruciferae.)



Summary Article: Horseradish
from Encyclopedia of Cultivated Plants: From Acacia to Zinnia

Horseradish, Armoracia rusticana Gaertn., Mey. & Scherb. (also known as Armoracia lapathifolia Gilib., Cochlearia armoracia L., and by other names), is one of the few plants of temperate climates cultivated for its value as a spice. When crushed, its root has a highly pungent taste and exudes a strong aroma that may burn the nose and eyes. Japanese wasabi is a different species, much harder to grow, but with similar taste and effect.


Armoracia rusticana is an herbaceous perennial belonging to the family Brassicaceae (or Cruciferae), which includes cabbages and mustards. The genus Armoracia contains only one species, native to Europe and western Asia. The origin of horseradish is uncertain; it is to be found in either western Asia or Eastern Europe. The plant is now found throughout Central and Eastern Europe and is cultivated around the world. In Europe, it encounters the combination of longer growing seasons with cooler temperatures and winter frosts as well as the moist and semishady environments it prefers. It can grow from seed but oftentimes does not produce any of its own. Mainly, horseradish spreads through underground shoots. It is not only being cultivated but is also found in the wild, often growing from pieces of roots left in the ground after cultivation was given up.

Horseradish typically grows two to three feet high, with elongated-elliptical leaves of up to 20 inches in length. Besides the plant cultivated as condiment, there is also a variety with variegated leaves grown as an ornamental. The root of horseradish, the part of the plant that is usually used (young leaves are also usable), is long, thick, and tapered.


The volatile chemicals responsible for horseradish's strong aroma are isothiocyanates, which are the types of chemicals that also give mustard its strong flavor. They form through the combination of precursor chemicals in the root when the cell membranes are torn, such as from biting or grating. The pungency of pepper (black pepper, Piper nigrum L.) or peppers (Capsicum sp.) is mainly felt in the mouth and especially on the tongue, whereas piperin excites nerve cells responsible for the perception of pain and capsaicin those normally reacting to heat. In contrast, the hot taste of horseradish (as well as wasabi and mustards) stems from volatile oils that have the greatest effect in the nose and also stimulate the flow of tears.


Horseradish is widely grown in Europe; most of the world's production is in the United States, where it is grown as an annual. It is propagated by planting side roots. Horseradish is preferably planted in deep, fertile, and moist soils to ensure good growth of the roots, which can reach three feet in length. However, it grows well in a wide range of conditions.

Horseradish was once employed as a medicine, not surprisingly since the pungent agents work strongly in the sinuses. Cultivation for the root, to be used as a condiment, is a more recent invention. Horseradish sauces were first made in Germany and Denmark, from where the use spread to Great Britain.


Horseradish roots are grated for use as a spice, often alone. British herbalist John Gerard, in his Herball of 1597, mentions the use of grated horseradish with a bit of vinegar, rather than of a mustard sauce, as a common German condiment accompanying fish. In Austria, a combination of horseradish and apples is popular with meats. In Central and Eastern Europe, it is also combined with vinegar and cream or with beets. In Great Britain, horseradish sauce developed into a typical accompaniment to roast beef. Horseradish sauces can be kept, but only for a short time; they can also be warmed but should never be boiled. The pungent principles are highly volatile so that fresh grating provides the best aroma. For commercial uses, horseradish flakes are also dried.

The different pathways through which pepper or capsicum, on the one hand, and horseradish (or mustard), on the other hand, feel pungent also translate into a different tolerance for hot foods: Europeans accustomed to the effect of horseradish sauce and mustard in the nose tend to have difficulty handling the “heat” of chili peppers; people accustomed to cuisines that employ chili peppers tend to handle the vapor of horseradish and mustard badly.

Wasabi, Japanese Horseradish

Wasabi, Eutrema japonica (Miq.) Matsumara, also belongs to the Brassicaceae but is a different species than horseradish. The part of the plant that is used is not the root but a rhizome, accounting for the green color of the spice. Horseradish, grated and colored by a food-coloring agent, is often used as a replacement for wasabi, especially as true wasabi is harder to grow and loses its aroma quickly. The taste of wasabi is somewhat fresher and purer than that of horseradish, but has similar burning and lachrymatory (tear-causing) effects. It is a typical accompaniment to sushi and sashimi. A little wasabi may be put on the sushi during preparation, but mainly it is mixed—by the customer, as desired—into the soy sauce used as a dip for the fish. The antimicrobial effects of wasabi are thought to protect from the danger that the consumption of raw fish may pose.

Wasabi is much harder to grow than is horseradish, ideally requiring cold flowing water and cool temperatures, but with little or no frost. Successful plantations have been developed in New Zealand and North America. With the rise in popularity not only of Japanese cuisine but also of hot and pungent tastes in general, one can increasingly find wasabi used as a spice, even for potato chips and other snacks. In traditional use, fresh root should be grated shortly before consumption. Wasabi is a peculiar ingredient in Japanese cuisine, indicative of a liking for hot tastes (also asserted by Japanese spice mixtures and sauces using chili peppers) in a culture of cooking otherwise best known for trying to keep the individual flavors of the ingredients as pure as possible.

Further Reading
  • Armoracia rusticana G. Gaertn., B. Mey. & Scherb. (Horseradish).” U.S. Department of Agriculture. National Resources Conservation Service. Plants Database.
  • Piper nigrum L. Black Pepper.” U.S. Department of Agriculture. National Resources Conservation Service. Plants Database.
  • Gernet Katzor's Spice Pages: Horseradish.
  • Gernet Katzor's Spice Pages: Wasabi.
  • Peter, K. V., ed. Handbook of Herbs and Spices. Vol. 2. Woodhead Cambridge, 2004.
  • Gerald Zhang-Schmidt
    Copyright 2013 by Christopher Cumo

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