Basic Information

Common Name: Eutrema

Scientific Name: Eutrema

Native Habitat: East Asia, including Japan, Korea, and parts of China.

History / Discovery / Cultivator

Eutrema is a genus of flowering plants belonging to the family Brassicaceae, which also includes well-known vegetables like cabbage, broccoli, and mustard. The most well-known species within this genus is Eutrema japonicum, commonly known as wasabi. While the genus Eutrema encompasses several species, the history and cultivation efforts are heavily dominated by wasabi due to its culinary significance.

Wasabi’s use dates back centuries in Japan. Its origins are intertwined with the mountains and riverbeds of the Japanese archipelago, where it naturally thrives. Historical records suggest that wasabi has been utilized for its medicinal and culinary properties since at least the 10th century. Initially, it grew wild, and locals harvested it from its natural habitats. As demand grew, cultivation efforts were initiated to ensure a stable supply.

The cultivation of wasabi is a challenging and meticulous process. It requires specific environmental conditions, including cool, shaded areas with a constant supply of fresh, flowing water. These conditions closely mimic the plant’s natural habitat, which is typically found in mountain streams and shaded riverbanks. The plants are typically grown in gravel beds alongside streams, where the water helps to regulate the temperature and provide essential nutrients.

Early cultivation practices were likely small-scale and involved transplanting wild wasabi plants into managed environments. Over time, farmers developed more sophisticated techniques to optimize growing conditions and improve yields. One of the key innovations was the development of different cultivars, each adapted to specific regions and growing conditions.

The cultivation of wasabi remained largely confined to Japan for centuries due to the specific environmental requirements and the lack of awareness in other parts of the world. However, as Japanese cuisine gained international popularity, so did the demand for authentic wasabi. This led to attempts to cultivate wasabi in other countries with suitable climates, such as New Zealand, North America, and parts of Europe. While some of these efforts have been successful, the quality and flavor of wasabi grown outside of Japan are often considered inferior to that of traditionally cultivated Japanese wasabi.

The intense flavor of wasabi comes from compounds called isothiocyanates, which are released when the plant’s rhizome (the underground stem) is grated. These compounds provide a pungent kick that is both stimulating and cleansing to the palate. Unlike the heat of chili peppers, which is concentrated on the tongue, the heat of wasabi tends to dissipate quickly, leaving a refreshing sensation.

Today, wasabi remains a prized ingredient in Japanese cuisine and is enjoyed around the world. However, authentic wasabi is relatively expensive due to the challenges associated with its cultivation. In many cases, what is sold as wasabi outside of Japan is actually a mixture of horseradish, mustard, and green food coloring. True wasabi has a complex and nuanced flavor that is far superior to these substitutes.

The story of Eutrema japonicum – wasabi – is a testament to the intricate relationship between humans and plants. It highlights the importance of understanding and respecting the natural environment to cultivate a unique and valuable crop.

Plant Care Summary

Botanical Insights

Adaptations

Eutrema japonicum (wasabi) has several key adaptations that allow it to thrive in its native environment. Its preference for cool, shaded, and constantly moist conditions is a direct result of its evolution in mountainous stream environments. The plant’s leaf structure is also adapted to capture diffuse light in shaded areas. The pungent compounds it produces, isothiocyanates, likely serve as a defense mechanism against herbivores and pathogens in its natural habitat. The rhizome’s ability to grow partially submerged in water allows it to access a consistent supply of nutrients and oxygen, essential for its growth and development.

Propagation Methods

Wasabi is primarily propagated through seed or rhizome division. Seed propagation is challenging and can take several years to produce mature plants. Rhizome division is a more common and reliable method. It involves carefully separating sections of the rhizome with attached roots and replanting them in a suitable substrate. Another method involves the use of stem cuttings, though this is less common due to lower success rates. Specialized propagation techniques are often employed by experienced wasabi farmers to ensure optimal growth and yields.

Toxicology

Eutrema japonicum (wasabi) is generally considered non-toxic to humans and pets. The plant’s characteristic pungency comes from isothiocyanates, which can cause a burning sensation in the mouth and throat if consumed in large quantities. However, these compounds are not considered harmful and typically dissipate quickly. Allergic reactions to wasabi are rare but possible. Symptoms may include skin rash, itching, or digestive upset. If you suspect an allergic reaction, discontinue use and seek medical advice.

Common Problems

Pests:

• Aphids
• Spider Mites
• Slugs and Snails

Diseases:

• Root Rot
• Fungal Leaf Spot

Other:

• Yellowing leaves: Often caused by nutrient deficiencies or insufficient light.
• Slow growth: Can be attributed to inadequate water flow or unfavorable temperature conditions.
• Rhizome rot: Often caused by poor drainage or fungal infections.

Rarity & Value

Rarity:

Authentic Eutrema japonicum (wasabi) is considered rare due to several factors. Its demanding growing conditions, including the need for cool, shaded environments with a constant supply of fresh, flowing water, limit its cultivation to specific regions. The plant’s slow growth rate, taking several years to reach maturity, also contributes to its scarcity. The high level of skill and expertise required to successfully cultivate wasabi further restricts its availability.

Value:

The value of wasabi is influenced by several factors, including its quality, size, and origin. Wasabi grown in traditional Japanese methods is generally considered superior and commands a higher price. Larger, more mature rhizomes are also more valuable due to their increased yield and flavor intensity. The presence of desirable characteristics, such as a smooth texture, vibrant green color, and intense pungency, also contribute to its value. Market trends and consumer demand also play a role in determining the price of wasabi.