Bamboo, a collection of ornamental grasses in the subfamily Bambusoideae, grows from an underground rhizome. Many varieties send out new rhizomes and rapidly fill a container. Repotting your bamboo will give the rhizomes more room to grow and develop. And if the plant is getting too big, you can always separate a few of the rhizomes and plant them in a new pot.
Turn your potted bamboo on its side in the pot and gently wiggle it free. When the rhizomes are densely grown into a pot, they tend to cling to the sides. If the root ball refuses to come out of the pot, break or cut the old pot away from the root system. Prune off any parts of the rhizomes that look damaged or diseased.
Select a new pot for your bamboo plant. Shallow, wide-mouthed containers are ideal for the lateral running nature of bamboo rhizomes. If your bamboo has been densely bound in the old pot, choose a new container that is twice the size of the old container. Make sure the pot has several drainage holes in the bottom to allow water to escape.
Fill the new container halfway with a mixture of equal parts rich seasoned compost, peat moss and coarse sand. This nutrient-rich, well-draining formula will provide your bamboo with nutrients while encouraging water to drain away from the rhizomes.
Place the bamboo into the new pot so that the rhizomes are slightly lower then the lip of the container. Fill in soil under and around the root ball. The base of the stems should be the same depth in the soil as they were in the old pot.
Run water over the newly potted bamboo until it seeps out of the drainage holes in the bottom, and place it in the sink to drain thoroughly. Water your potted bamboo every three to four days or when the soil begins to feel dry to the touch. Keep the soil moist but not saturated.