Minecraft wiki entry for Bamboo, associated text: The appearance of bamboo changes as it grows. When first placed, it takes the form of a small shoot, which has no hitbox. When it grows one block taller it grows to 2 pixels in length and width and the top block has leaves coming off it. At 3 blocks, the top 2 blocks have leaves and at 4 blocks the bamboo expands to 3×3 pixels. At 5 blocks tall, the top 3 blocks have leaves on them. As the bamboo grows, the leaves move up and stay at the top 3 blocks. Destroying a block of bamboo does not change the appearance of the blocks below it. Bamboo is oriented at a random position in the block that it is in. Bamboo, grass, sweet berry bushes, and ferns are the only plants that change their hit boxes as they grow.