Eutrema japonicum, commonly known as wasabi or Japanese horseradish, is a semi-aquatic perennial herb cherished for its fleshy rhizomes, which are finely ground to produce "true" wasabi. This naturally green, spicy paste is a staple in Japanese cuisine, often used as a condiment but also as a substitute for horseradish. Beyond its culinary uses, wasabi is known for its medicinal properties, including antibacterial and anti-inflammatory benefits, and is a rich source of vitamin C, vitamin A, and trace amounts of iron, helping to boost immunity.
In addition to its practical uses, wasabi is a visually appealing addition to any edible landscape. The plant grows up to 12 inches tall and wide, with all parts being edible. It produces attractive leafy green foliage and small clusters of tiny four-petaled white flowers from late winter to early spring. These flowers are followed by dry, elongated fruits that are grooved lengthwise.
Eutrema japonicum belongs to the mustard family (Brassicaceae) and is native to Japan and Korea. It thrives in the wild along rivers and streams in cool, mountainous regions. The plant has an erect habit and grows slowly, with its rhizomes taking 2 to 3 years to reach a harvestable size of about 1 inch in diameter. When ready to harvest, the entire plant is pulled from the ground, and the rhizome is grated immediately for the best taste. Alternatively, the roots can be refrigerated for up to a month or dried and ground for a longer shelf life. Propagation can be done through plantlets that grow around the primary plant or by dividing the rhizomes.
Wasabi prefers temperatures between 46 to 70°F and thrives in locations with dappled sunlight to part shade. It requires moisture-retentive but well-draining soil and should be kept well-watered, never allowed to completely dry out. Mass planting wasabi in a shade or water garden can create a lush, productive landscape.
For gardeners seeking a unique and beneficial plant, Eutrema japonicum offers both beauty and utility. Its distinctive flavor and health benefits make it a valuable addition to any garden, providing fresh wasabi for culinary adventures and a hardy, attractive green for the landscape.
