Wasabia japonica is a perennial brassica, native to the Japanese mountains. Semi-aquatic, wasabi grows in the wild alongside streams with large trees overhead that provide a canopy of shade. Wasabi will also grow very well in soil in the garden in a damp shady spot. Wasabi will also grow into a large houseplant in a pot.
Wasabi should be planted in free-draining, fertile soil. In a pot use standard compost with added perlite or bark and gravel in the base of the pot. Guard from snails and slugs and provide shade over the summer. Wasabi is 100% edible so leaves, leaf stems and flowers can all be enjoyed while you wait 18 months for the rhizomes to develop at the base of the plant. Once rhizomes are present you can choose to pull the whole plant and grate your own fresh wasabi. There will be several small offshoots / plant-lets at the base of the harvested plant, these can be separated and re-planted to continue your fresh wasabi growing.