Horseradish

The fiery bite of horseradish adds its signature flavor to many dishes, and it also makes a nice patio plant.

Horseradish root (Anna reg) CC BY-SA 3.0

Horseradish (Armoracia rusticana) is a member of the Brassicaceae family, making it cousin to watercress, mustard, wasabi, radishes, broccoli, turnips, and cabbage. Scientists used to call these types of plants Cruciferae. The word cruciferous refers to the flowers, which have four petals, resembling a cross. Supposedly, the Oracle at Delphi told Apollo that horseradish was worth its weight in gold, so it’s been around for a really long time. Today, let’s learn how easy these plants are to grow at home. ​

How horseradish grows

The horseradish that you buy in the grocery store is usually peeled, pureed, and pickled. Grown for its root, horseradish plants can grow over 4 feet tall, but mine have never gotten bigger than a couple of feet all the way around. Horseradish needs a long growing season to get started. They also need a chilly winter to induce dormancy. We have both, here in the Bay Area. Horseradish plants spread underground and can become invasive, which is one reason why they make good container plants. As they age, roots become woody and unusable as food, but they can still be used to start new plants. The first leaves usually look distinctly different from the normal large lobed, tapered, or heart-shaped  leaves, so don’t pull them out by accident!

Horseradish as food

Roast beef, Bloody Marys, and salmon are always made better with horseradish. You can buy ‘prepared’ horseradish, which contains grated root and vinegar, or you can buy ‘horseradish sauce’, which adds mayonnaise. Growing your own horseradish allows you to create a unique recipe of your own. But, when you first dig up your horseradish root, you may feel as though you did something wrong. The root itself has no smell. It isn’t until the root is chopped up that certain enzymes are released. These enzymes break down plant tissues, producing mustard oil.

​It is the mustard oil that lights up your sinuses when you take a bite. Chopped or grated horseradish turns brown and bitter when left untreated, which is why vinegar is always added as a preservative. The longer chopped horseradish sits before the addition of vinegar, the hotter it gets. Whether you grow your own horseradish or buy it already prepared, you really should try this recipe for remoulade. Your tastebuds will thank you! Horseradish leaves are edible, as well. Use them sparingly in a salad for the same fiery bite you get from the root.

How to grow horseradish

Horseradish plants are normally started from crowns in the spring. Attached to the crowns are slender roots called ‘stecklings’. Spread the stecklings out just under the soil level in a large (24 to 36 inch deep) container, or in the ground. Cover the stecklings with soil, up to the crown, and water well.

​Horseradish grows best in partial shade and plants need to be watered regularly in summer. In winter, your horseradish plant will die back to soil level. This is when you dig up the root and divide it. Keep the largest root for yourself and return the remaining roots back to the container or garden spot. Then cover the area with some straw or mulch and wait for spring.

Horseradish makes a nice patio plant

Horseradish pests and diseases

Cabbageworms, leafhoppers, and aphids may feed on your plants. Horseradish is also susceptible to viral diseases, such as beet curly top (rhabdovirus group) and turnip mosaic (potyvirus group). These diseases are spread by leafhoppers and aphids, respectively.

Did you know that, when you buy wasabi, what you are probably really getting is horseradish? Wasabi plants are becoming scarce and horseradish is easy to grow. Manufacturers use the fact that these plants are closely related to mislead their customers. (Shame on them!)

You can add a horseradish plant to your patio, balcony, or garden for lovely spring and summer greenery, and year round flavor!