Bamboo, despite some species' large size, is a member of the grass family. Its addition to an area adds a tropical flare to both indoor and outdoor locations. As with all container grown plants, bamboo will require replanting from time to time. Since it spreads by underground rhizomes, bamboo will eventually take up all the available space in the container with its roots. Replanting bamboo is not hard and your plant will be healthier and happier for it.
Change out the bamboo into a larger container and trim the roots, when watering the plant it seems to soak up all the water and still wants more. This generally means the roots have taken up all the space inside the container and the plant has become root bound.
Select a container that is one to two sizes larger than the present one. Do this if you do not want to trim the roots and divide the plant but leave it at its original size. Choose a container that has a top opening as wide as the bottom of the container. If you select a container with a small opening, you will not be able to remove the plant when repotting it.
Remove the bamboo from the container and decide if you want to divide the plant into two separate plants. Use a handsaw and saw through the center of the bamboo's root ball, if dividing it. Saw approximately the bottom ten percent of the root ball off to promote the bamboo's roots to grow new shoots.
Soak the root ball in a bucket of water for approximately one hour before replanting into the container. Keep the root ball moist if you do not intend on repotting the bamboo immediately. Soak the root ball and wrap in plastic wrap if you intend on replanting in one or two days. It is imperative to keep the bamboo's root ball moist.
Fill the bottom third of the container with a material such as pea gravel. This will help promote good drainage and will give the root system better air circulation.
Select a potting mix that drains well and has organic material in it. Incorporate a slow release fertilizer such as Osmocote into the potting mix before placing into the container. Pour the amount of fertilizer specified on the package into the soil and mix it together with your hands.
Fill the container one third full of potting mix. Place the bamboo into the container and fill the rest of the way up with soil. Pat the soil down around the root ball with your hands to firm it up.
Water the newly replanted bamboo well. Allow the water to run out of the bottom of the container. Keep the bamboo watered regularly to keep the soil moist but not flooded.