Native to Japan, wasabi is a perennial plant closely related to mustard and has a strong hot flavor. The root is ground into a green paste as a staple condiment. In some cases, it is sold as a powder then mixed with spring water to make a paste.
In American cuisine, it is generally regular horseradish mixed with mustard and green food coloring.
The plant requires shade, cool air, and running water to grow, and is unsuited for cultivation in many locations within the U.S.
Typically, a harvested root is 2 to 4 inches in diameter and 6 - 12 inches in length. Fresh wasabi can be stored for up to 4 weeks if refrigerated.
Wasabi plants prefer 54 to 59°F, may become heat damaged at temperatures above 82°F, and will slow or stop growing at temperatures below 46. Extended exposure to frost will damage the plants.
There are many variations of plants and styles of growing. In a typical growing system, two wasabi stems can be produced per square foot and be ready for harvest in 16 to 20 months.