Though often compared to horseradish, wasabi is, in fact, an unrelated herb. In Japan, it grows wild near freshwater streams, but it is also cultivated widely. Although all of the plant is used as food, it is the green root that is grated and eaten with sushi and sashimi, when it is sometimes mixed with soy sauce. Most of the so–called wasabi—in powder or paste form—available commercially is dyed horseradish. Real wasabi is expensive, and if seeking it, ask for hon (real) wasabi.
Also known as — wasabe