Bamboo is a very tall, hollow grass in the Subfamily Bambusoideae. It's very prolific and can out compete other plants and grow tightly packed together. Some species have been known to grow 3 feet in about 24 hours. Bamboo is most known and cultivated in Eastern Asia, but some species can be found around the equator in Africa and South America. It is doubtful that historical Vikings ever came across bamboo.
In reality, bamboo is a widely used plant with many uses. It can be used as a building material, for food, tools, furniture, historically as a writing surface, weapons, textiles, and musical instruments.
|“||We'll get a little hut somewhere with a bamboo divider in the middle ... [src]||”|
In the episode, "A Gruff Separation", The Twins take the Thorston Induction Trials, but are told that only one of them can complete it and become a full member of House Thorston. After the final test, the Twins realize that they should stay together rather than leaving the other behind. Tuffnut suggests building a little hut for each other.