Wasabia japonica WASABI (plant)

Wasabi, Japanese horseradish, also known by its botanical name Wasabia japonica, is a perennial and rare plant from the Brassicaceae family. It can reach a height of 20 to 30 cm at maturity. It is native to Japan but also thrives very well on the European continent.

The dark green edible leaves of the Japanese horseradish are thick and round in shape.

Wasabi seeds for sowing, from Eutrema japonicum, are small, thin, elongated, and black. They usually ripen at the end of May, just after flowering. It is necessary to sow them quickly in a seedling starting mix and then stratify them to achieve an excellent germination rate. To obtain viable seeds, it is recommended to plant them in open ground to encourage rapid and natural pollination.

Its flowers are white and small, often used as a decorative garnish in Japanese cuisine.

Its roots are long, thick, and greenish-white in color.

How do I properly plant my wasabi?

• Transplant the plant into a 1 to 3-liter pot with a mixture of potting soil and clay pebbles, or plant it directly in the ground by digging a hole 20 cm in diameter.
• Water generously at the base of the plant immediately after planting.
• Place the pot in a shady and cool corner.

- Good to know!

Wasabi is very sensitive to excessive heat above 20 °C.
People often say that wasabi is impossible to grow that is completely false!
I have been growing wasabi for over 15 years; it simply likes cool temperatures and shade two conditions that must be strictly met.

What type of soil should I use?

It needs a slightly acidic pH soil, rich in organic matter, and well-aerated ground.
Sand can also be added to the mix, but in very small quantities for its draining effect.

Does wasabi need a lot of water?

Japanese horseradish grows in a relatively humid and cool environment.
For watering, twice a week is sufficient; never let water stagnate in the saucers (risk of root mold).

What is the best location for growing it?

It adapts to all kinds of light but prefers shaded locations. It is essential to acclimate it when moving it from one exposure to another.
Regarding artificial lights for indoor cultivation, horticultural neon lights or MH lamps are preferred.

Is it hardy? What is its ideal growth temperature?

Its growth temperature ranges from 10 to 20 °C. Beware of heatstroke when temperatures rise above 30°C.
It is particularly resistant to very low negative temperatures.
Its USDA hardiness zone is 7.

How can I easily propagate Eutrema japonicum?

There are two ways to reproduce it: either by sowing seeds in the spring or by dividing the base of the plant throughout the year.

What diseases and pests should I watch out for?

Slugs and snails unfortunately love its leaves. To combat these attacks, I use wood ash.

What care should I give it once it's planted?

Be sure to remove any dead or yellowing leaves at the base of the plant.
Add slow-release fertilizer after nine months, or do as I do and simply repot the plant in fresh growing medium.

Why grow Wasabi at home in your garden?

A Treasure of Japanese Cuisine

Genuine Wasabi is a demanding plant whose fresh rhizome offers a unique spicy heat, much more subtle and aromatic than chili.
By growing your own plants from the high-quality, robust, and well-rooted specimens currently available on the Ethnoplants website, you can experience the true flavor of this premium condiment far removed from industrial imitations made of horseradish and green dye.

Subtle Flavors and Uses of the Plant

Unlike classic pastes, freshly grated wasabi releases a volatile pungency that fades to reveal a refined vegetal sweetness.
All parts of the plant, such as the leaves, flowers, and roots, are edible, allowing you to create artisanal sauces and condiments of incomparable finesse to elevate your sashimi and fish dishes.

This article was written by Julien on 09/25/2026.