It seems that every time I read, watch or listen to anything about cooking, one of the ingredients mentioned is the herb wasabi. I didn't know anything about it, so, after hearing its unique name several times, I decided to research it.
Wasabi (Wasabia japonica) is a plant that has been used by Japanese cooks through many centuries. It's a member of the crucifer family, which includes mustards, broccoli and cauliflower. Wasabi is prized for its fleshy root, but its leaves are also flavorful.
My research revealed that wasabi grows native next to mountain streams in Japan. It needs cool water to maintain its roots, but it also needs the shade of neighboring trees in order for it to grow well. These are conditions that won't be found in my garden in the center of the United States.
There are gardeners in the United States, however, who are growing wasabi successfully in man-made structures that keep the plants shaded and the roots cooled in a gravel-and-water bed. My first thought: It seems like more work than it's worth. Then I purchased a small bottle of canola oil mixed with grated wasabi at a gourmet food store. A smile spread across my face when I tasted it, and I decided that it would be great drizzled over grilled veggies.
It had a sweet-hot flavor that subsided quickly, but left a pleasant remnant of the flavor. In short, it tasted like horseradish.
Upon further research, I discovered that the reason I may have thought of horseradish when I tasted the oil is because both of these plants are members of the crucifer family. Being in the same plant family, the roots of these plants contain oils that provide a sharp, hot flavor.
There was another reason horseradish came to mind: what I had purchased was horseradish. The root of wasabi is green, while the root of horseradish is white. But I read that it's common to sell horseradish dyed green to pass for its rare, expensive cousin.
If wasabi tastes similar enough to horseradish to pass for it, why would I go to the trouble of trying to grow this herb, especially when horseradish does so well in my climate and soil?
Horseradish is one of the most forgiving herbs in my garden. Even with little care - just some added water - it will still produce plenty of fiery roots for the year's use. It's a perennial plant, but it should be dug up each year and replanted with a piece of root to keep the roots from becoming woody and unusable in the kitchen.
Horseradish can be harvested in the fall, once frosts have stopped the plant from growing, or in the spring, before new growth resumes. When harvesting, make sure to save several lateral roots for new plantings in the spring. Mark the roots to be used for new plant stock in a way that the upper part of the root can be recognized when it's time to replant - so it doesn't need to grow from the bottom up. Replanted roots should be placed at a 45 degree angle a couple of inches below the soil surface to help give numerous roots room to develop.
To prevent shriveling, store harvested roots in a refrigerator until it's time to use them. Roots of horseradish will turn green if they aren't stored in the dark. Make sure they're covered or wrapped in a manner to keep them out of the light.
When processing horseradish, most gardeners peel the root, then grind it in a blender until pureed. Vinegar and spices are then added for use as a condiment. Vinegar stops the reactions of grinding the root oils, so if a stronger taste is desired, wait longer to add vinegar. Ground horseradish has a short shelf life, as far as taste goes, so you should only process what you'll use in a month or two.
Wasabi may not find its way into my garden, but my research on it has given me respect to the often-overlooked horseradish. Instead of simply making a condiment for sausage and roast beef, I now know I can add a few sprigs off a grate to my grilled veggies ... and who knows what else!