Eutrema japonicum

Eutrema japonicum, Wasabi, is the well-known Japanese horseradish popular as a condiment for sushi. It has a reputation for being difficult to grow which is really only applicable if you are growing it on a mass scale as a commercial crop. Growing it in your garden, your allotment or - hopefully - your exotic garden is no more difficult than growing many a water marginal. It favours a moist, humus-rich soil and a semi-shaded location. It is very quick-growing and has a large attractively round kidney-shaped leaf resembling an Asarum and a smallish rather elegant white flower on a whiskery stem. Its large circular foliage works well with other perennial foliage plants and as an added bonus you always have the choice of adding it to your cuisine. Both the freshly-grated stem and the leaves can be eaten.

Slugs are rather fond of eating them as well...