Order: Brassicales
Family: Brassicaceae
Genus: Armoracia
Species: A. rusticana


Horseradish is a hardy, edible perennial which is widely cultivated for its large white, tapered root. An intact, freshly-lifted horseradish root is almost absent of any distinctive aroma. However when cut or grated enzymes are released producing a mustard oil which is capable of irritating the mucous membranes of the nose and eyes. It is the mustard oil (allyl isothiocyanate) which gives horseradish sauce its characteristic kick.


The production of Allyl isothiocyanate is actually used by the plant as a defense against herbivores. When an animal chews the plant, the allyl isothiocyanate is released, repelling the animal. 

Native to southeastern Europe and western Asia, it is capable of reaching heights of up to 1.5 meters when grown in subtropical and tropical climates. Be that as it may, in northern European climates the horseradish plant is more likely to grow to between 70 - 100 cm. It has large, dark-green leaves and during the early summer small, white, four-petalled, cross-shaped flowers are produced.

Horseradish will thrive in any ordinary, well-drained garden soil, either in full sun or partial shade. Dig in plenty of well-rotted farmyard manure or garden compost before planting. Be aware though that once established the long roots of the horseradish are difficult to eradicate should you decide to grow a different crop in the same area as time goes on.

Horseradish are usually purchased as pre-packed roots early in the spring. Known as thongs, they will usually be approximately finger thick and between 10-15 cm long. Plant the roots at a slight angle with the sloping cut at the bottom and the flat cut at the top. each thong should be planted 30 cm apart and in rows spaced 50 cm apart. The top of the thong should will only need to be 5 cm below the surface. Thoroughly water the newly planted roots in order to help them establish and keep them well watered in dry weather.

Lift the roots as required during the summer. Older roots can be lifted, have their foliage removed and stored in boxes of soil or sand for use over the winter. Any roots left in the ground will become woody, at which point they will no longer be suitable for producing sauce. Of course they can always be dug up in the following spring and re-divided to start off new plants.

To maintain vigour, dig over and manure the beds each winter.

About the Author

The 'Seeds of Eaden' website is the brainchild of professional horticulturist and multi-award winning gardener Simon Eade. After six years of study; two years 'Retail Horticulture' at Hadlow College, then four years Commercial Horticulture at Greenwich University, Simon has worked in a number of 'fields' within the industry for over twenty years. Most notably, managing the prestigious Alexandra Palace garden centre in London. Since then he has become an internationally published writer, and author of the popular 'Garden of Eaden' blog.

Simon Eade is also a recipient of the Royal Horticultural Society's Banksian medal

You can contact the 'Seeds of Eaden' at