Wasabia japonica – Wasabi is a tricky plant to grow well but when you get the right conditions it thrives. You have to look at where it originally comes from and where it is grown commercially in Japan for clues.

I have been growing it now for a few years and it just loves the local Blue Mountains climate at 1000m. I have set up a specific shade house environment to grow it and the plants are responding well and produce good new leaf during about 4 months of the year. The rest of the year they kind of just hang around growing slowly.

Here is a bunch of plants I am growing behind shade mesh.

In Japan they grow generally in the boggy edges of streams in high mountains areas under the shade of large trees. This says a lot about what they probably like. Shade but with short periods of filtered sunlight, regular water turnover, low but constant variation in nutrient levels (as detritus moves along the streams) and low seasonal variation in temperatures that max out at about 20c.

Supposedly the best tasting are grown in hydroponic setups, but I think the results in soil are fine as long as you have healthy looking leaf and stem with no weird colouration or abnormal growth. They can get a bit dirty sometimes with water splash throwing soil up on the stems and leaf.

There are only a few varieties generally available in Australia, and only a few major quality producers of stem and leaf such as Shima in Tasmania. I currently am growing Mazuma and Daruma.

I grow mine mainly for leaf and stem production. These are really nice chopped in salads. The tiny leaves are very decorative  as well. The larger the leafs the crunchier they get.

It takes about 2 years to get a decent sized main stem grown and it is obviously the end of the plant when you harvest it. The leaf can get up to about 40cm across when growing really well, but mine are usually a max of about 25cm. I am sure this would also be based on the varieties you grow.

The plants do tend to send off nice new ‘shootlings’ as divisions after about a year of growing well.

It is NOT good if the ambient temperature around them goes above about 20c. Keep the plants down near the ground if possible to reduce temperature variation and help keep the air moisture levels high. This can also be done by misting them regularly. Just keep in mind their cold mountain stream origins.

The chemical reaction that gives Wasabi it’s distinct taste only lasts for about 15mins and is started when the cells walls are ruptured by maceration or cutting and builds up over about 5 mins. After the chemical reaction completes the plants just have a pleasant green ‘grassy’ flavour.

I have seen many people try to grow these even in the mountains up here and fail dismally and quickly. It is not a plant to try growing if you don’t observe carefully. But ironically once you get the general environment set up correctly they seem to be very rewarding and hardy plants.

http://en.wikipedia.org/wiki/Wasabi

This a small Mazuma plant.

I am primarily interested in growing and supplying to other people Wasabi leaf for salads and decorative additions to meals. The leaf and stalk are rather tasty but subtle.