28/11/23 ... I have just potted up a batch of new seasons seedling wasabi plants (into 10cm pots) and they should be ready to sell in 6-8 weeks.
Wasabi japonica is a native condiment crop of Japan. It is the plant that makes the fiery green paste used in Sushi and Sashimi.
The thick main rhizome stem is harvested after growing for 2 years. In Japan they grate it at the table on a Wasabi grater as you dine. NZ grown Wasabi root sells for $110 per kg.
Wasabi leaves/stems are edible & have a mustardy flavour. So you don't need to harvest only the rhizome, grow Wasabi like a perpetual vegetable plant.
The leaves/stems are blanched quickly, then dressed with Japanese style soy dressing (soy, yuzu juice, sesame oil, salt/pepper) and sprinkled with toasted Sesame seeds or Bonita flakes. You can also fry Wasabi leaves for a crispy unique garnish.
Wasabi stems can be pickled in rice vinegar and sugar and served as a condiment.
Wasabi Plants are an evergreen perennial and a member of the mustard family. It is a native plant of Japan where it grows naturally in wet places alongside mountain streams. In Japan, high quality Wasabi is grown in mounded gravel water beds fed from cold mountain streams.
Wasabi plants need a cool, moist, shady spot and protection from winter frost. The plant is quite fast growing and clump forming in the correct conditions.
You can grow Wasabi in pots & tubs with a modified potting mix, 2 parts premium potting mix, 1 part Pumice, 1 part Peat Moss.
There is a a small NZ Wasabi growing industry located in the central south island. Most of the produce is exported to the US for herbal and pharmaceutical use. None is sold to Japan for several reasons. A small amount is sold as fresh root to NZ restaurants, and some is processed into a NZ style Wasabi paste.
The last couple of photos is of a friends naturalised wasabi garden in Whitemans Valley, Upper Hutt. The wasabi grows under the shaded canopy of a Pine Block and there is a natural small spring stream that meanders down the hill and never floods. Perfect growing conditions! She planted just 3-4 wasabi plants at the top of the stream and over the years, the wasabi has naturalised the entire length of the stream. It's an amazing sight!