Mustard plants are a type of plant that produce a condiment known as mustard. The most common types of mustard plants are cress, wasabi, radish, and cole. Cress is a leafy green vegetable with a peppery flavor, wasabi is a Japanese condiment made from the root of the Wasabia japonica plant, radish is a root vegetable with a spicy flavor, and cole is a type of cabbage. Brussels sprouts are a type of cruciferous vegetable related to cabbage, kale, and broccoli, and they are also a type of mustard plant.