Pruning and Thinning Bamboo

Starting after the second summer of growth, it is good for the bamboo to be thinned. Take away only a few of the oldest canes (these will most likely be the smallest in the clump). Do not take more than 1/3 of the total mass of the clump, and do not take any of the newest growth. Once you have decided which canes to cut, cut them near the base, just below the ground.

After this initial thinning:

1. Prune out culms so they are about 6-9" apart, cut them at or below ground level. This allows for plenty of space for new shoots to rise from the ground, eventually replacing the old ones.
2. You can thin the clump out every year or two or three - again being careful not to take too much of the newest (youngest) part of the plant, as that is the most important for its future good health.
3. You can thin the clump each year carefully making sure that there are no canes over 3-4 years of age. You can also cut out any canes that are under size, or going in a direction which you don't like (like too close to the house, or too close to the path, etc.). The 3-4 year old canes are at their peak of strength if you are interested in using them for any kind of craft or construction purpose.

You can also prune out branches to reveal the canes or to create a more airy feeling. If you are of a mind to have a highly manicured hedge you can use hedge trimmers to create whatever shapes you like.