Mochi Isle
Bamboo is grass · Bamboo ValleyScience for kidsWhy is bamboo a grass and not a tree?
In short: Bamboo belongs to the grass family, the same family as rice, wheat and lawn grass. Its stems are jointed and usually hollow, and they never thicken year after year like a tree trunk, so bamboo is really a giant grass.
How it works
A tree adds a new layer of wood under its bark every year, so its trunk gets wider and shows growth rings when it is cut. Bamboo cannot do this. A bamboo shoot comes out of the ground about as wide as it will ever be, and a bamboo stem has no growth rings inside.
The raised rings on a bamboo stem are called nodes. Between the nodes the stem is usually hollow, like a row of tubes joined end to end. The nodes act like walls that brace the tube, which is why bamboo is light but strong. A few kinds are solid, filled with soft pith.
Bamboo grows remarkably fast, and some kinds are among the fastest-growing plants on Earth. A new shoot can reach its full height in just a few months, because every section stretches at the same time, a bit like pulling out a telescope.
Where to see it in New Zealand
New Zealand has no native bamboo; the bamboo in gardens and parks was brought here from elsewhere. But bamboo's grassy cousins are everywhere. Toetoe, the tall native grass with feathery plumes, grows along coasts, wetlands and roadsides, and the tussocks of the Canterbury high country are grasses too.
Try it together
Find a bamboo garden stake. Run your fingers over the nodes and look into the cut end to see if it is hollow. Then find a grass stem that has gone to seed and look for its tiny nodes. Same family, same clues.
Kids also ask
Bamboo is as hard as wood, so why is it called a grass?
Scientists group plants by their flowers and body plan, not by how hard they are. Bamboo flowers look like rice and wheat flowers, and its stems have nodes, so it belongs to the grass family.
Does a bamboo stem get thicker every year?
No. Each stem stays about as thick as it was when it came up as a shoot. A clump gets denser, and newer stems can come up thicker, because the underground stems grow stronger over the years.
When a giant panda eats bamboo, is it eating grass?
Yes, in a way. Bamboo makes up almost all of a panda's diet. But a panda's gut is built more like a meat-eater's, so it digests only a little of what it eats and spends many hours a day feeding.
In the game, “Bamboo is grass” is a nature card on Bamboo Valley.
Your child finds this card by reaching the right place or meeting the right weather on the island, and lights it up by answering the question on the back. Tap the button below and the game shows your child which island it is on and how to find it. Mochi Isle is a browser learning game for ages 5 to 18; the main island and the daily lesson are free.
Find “Bamboo is grass” on the island ↗ All cards from Bamboo Valley