Let’s talk horticulture. Wasabi is a rhizome type of plant. It is easy to think of the part we eat as the root of the wasabi plant, but it’s actually the stem. A rhizome is the part of the stem that develops underground. They spread out horizontally, parallel to the soil, and sprout up new plants. Asparagus and bamboo are also types of rhizomes.
A similar type of plant is a tuber. And many tubers are also underground stems, like the wasabi plant. The stem tubers we all know and probably eat are the potato and carrot. There are also root tubers, like the sweet potato.
One of the main differences between a rhizome and a tuber is that tubers do not spread out horizontally.