While I was growing up, bamboo shoots were an exotic vegetable that came from a can bearing foreign characters — foreign to my American eyes, that is. Despite the slight preservative and tin-can flavor, the tender shoots remained one of the delicacies that deepened my interest in the cuisine of countries far away. I would not be exposed to the fresh shoots of giant bamboo grass until visiting Asia as a young man.
Spring is the universal season of rebirth and renewal. There are many food items (a good portion of them vegetables) that are enjoyed in the spring, during the very early stages of this rebirth growth cycle. Takenoko, bamboo shoots (literally "children of bamboo") are eaten fresh from late February, continuing through midsummer in some parts of Japan. The very tip of the bamboo shoot, which still lies under the surface of the earth or has just broken through, may be harvested and cooked while still young.
There are many varieties of bamboo and almost all of them may be harvested and eaten during their early-growth phase. The varieties that can be eaten after they are fully grown as well are rare.