Plants with bite

The first I learned of the existence of wasabi was while visiting Melbourne in my younger days. Having a semi-rural outlook, the idea of dining in a Japanese restaurant was the epitome of exotic. Alongside the quail eggs, seaweed and rice was a seemingly stingy serving of avocado. Well, it turned out not to be avocado! Once I recovered from my nose exploding, I thought to myself, “That’s quite good actually!”

A productive food garden isn’t just about growing food for sustenance, it should also include edibles that add flavour and interest to our food, and that’s where plants such as wasabi and my other fiery favourites, mustard and horseradish, come into play. These are all members of the Brassicaceae family, but compared to cauliflower and broccoli, they are the brassica bad boys.

Wasabi

All parts of the wasabi plant are edible, but it’s the stout stems that are used for grating and making wasabi paste. It can take up to two years for the plant to develop a decent stem, so you need a bit of patience. One consolation is the stem will have developed lots of offshoots that are easy to remove and replant, so over time, you can build up stocks and develop a steady supply.

Wasabi (Eutrema japonicum) is a semi-aquatic perennial herb suited to cool temperate climates. If you picture a typical Japanese scene – a cool, flowing stream with mossy rocks shaded by maple and cherry trees – then you have an idea of the conditions wasabi needs to thrive.

While not many of us can claim to have a picturesque stream flowing in our backyards, if you plant in compost-rich soil in a semi-shaded spot and keep it moist, you’ll do pretty well. If remembering to water is a problem, consider a simple irrigation system. Plants like a slightly acidic soil (a pH of 6–7), and thrive on a regular application of organic fertiliser.

You can also grow wasabi in a pot, and it’s a good option if you are in a warmer marginal area, because you can move the pot to the coolest part of the garden as temperatures rise in summer. They stress when it’s over 25°C. Sometimes on hot days I’ll leave my wasabi pot soaking in a bucket of water to keep it refreshed. In winter, you can shift it to a protected place out of reach of damaging frost.

Horseradish

Getting hold of my first horseradish plant was easy, as I had plenty of mates who were willing to divide a bit of the root for me to take home and grow. There are also many online suppliers that can post you a piece. This is a good plant to have on hand for adding a little nasal fire to your eating experience, and it’s easy to prepare. All you need to do is dig up a fleshy root, wash it and grate it onto a meal.

Horseradish (Armoracia rusticana syn. Cochlearia armoracia) will grow in most areas and it’s much easier to grow than wasabi. In fact, it has the tendency to take over. If you leave any part of the root behind when harvesting, it will likely regrow. For this reason, I normally plant it in a deep pot buried in the ground, in an attempt to keep it corralled. 

Planting is best done in autumn or early spring, in compost-enriched soil. It likes full sun but appreciates a little afternoon shade in warmer areas. It responds well to regular watering and feeding but is pretty tough, so will cope with some neglect.

It needs one or two growing seasons before you have sizeable roots to harvest. After harvesting, you can keep washed roots wrapped in a damp cloth in the fridge for a few days. Another option is to grate and preserve it in a jar in equal parts vinegar and water with a little salt. Seal the jar tightly and it will keep in the fridge for a few weeks.

Mustard greens

This is the easiest of the brassica bad boys to grow and harvest. Its spicy leaves are great for sautéing with garlic in a little oil or adding to a salad when you need that fiery hit, and you don’t have to wait long for a harvest. It’ll grow in all areas and, like many leafy crops, prefers cool, mild conditions, rich organic soil and regular watering and feeding. There are a number of varieties, but red mustard greens is a standard winter standby in our household for its warm, peppery flavour and splashes of colour in the garden.

Header image credit: iStock

Want to learn more about horseradish and mustard greens?

Horseradish

Mustard greens