Tropical Bamboo® Nursery & Gardens

A frequently asked question at Tropical Bamboo Nursery & Gardens is, "Can I trim my bamboo?" or "How do I trim and maintain my bamboo?"  The answer to the first question is not only yes you can, but yes, you should trim your bamboo!  I'll describe the methods and provide some tips but first it is important to understand why your bamboo should be trimmed.

A clumping bamboo is usually planted as a small start, often one or two small culms that were growing in a small container.  After planting, the roots and rhizome develops in the ground.  New shoots emerge and become new culms – each new shoot progressively larger and taller than the previous.  After about 18 months, the clump should be a mixture of thin culms (pencil diameter), medium culms (cigar sized), and maybe a couple of larger culms.  The larger culms could even be up to a few inches in diameter, depending on the species and growing conditions. 

 The size of the emergent shoot determines the ultimate height of the culm. Once the shoot finishes shooting (a couple of months) branches form and then leaves develop.  There is very little change in overall size after the culm has developed leaves.  It is finished growing and will only replace leaves and some branches if trimmed or damaged. 
It is important to understand that bamboo is a woody grass, not a tree.  Each new shoot that develops into a culm has a finite life.  This may be a couple of years or seven or eight years.  Eventually, a culm becomes obsolete within its clump and will drop its leaves, dry out, and turn a tan color.  Their life, or usefulness within the clump, can be affected by other factors besides time.  Attrition (culms rubbing together or against other objects), sun scalding, storms, fungus, insects, birds, or animals all can accelerate the demise of a culm. 
When growing clumping bamboos as ornamentals, culms and branches should be removed each year (after an establishment period of at least 1 year).  Never remove more than 1/3 of the total mass of the clump.  The goal is to simply remove unattractive or uneven culms or branches to reveal and/or highlight the most attractive culms in the clump.  Also, space will be created for new shoots to develop without obstruction.  The newer culms will always be brighter and cleaner looking.   Older culms, beyond four years old, will start to look dingy and may have stains or areas of discoloration.  You'll want to remove the oldest culms but sometimes you'll have to keep some of them to maintain balance.  You don't want to create a gaping hole in the overall form of the bamboo clump.  Regardless, there should never be dead, tan culms or branches within the clump. 
Tools for clump maintenance include reciprocating saws with pruning blades, hand saws, loppers, and hand pruners.   Chain saws can be used but are not recommended.  The cuts are not clean as the bamboo fibers are pulled, leaving a shredded appearance. 
Culms should be cut flush with the ground leaving no stump above ground level.  The cut culm can be pulled out of the clump from the bottom as the branches will fold back.  Branches should be cut flush with the culm as cleanly as possible.  Try to make most cuts from the underside of the branch upward.  If you cut from the top downward, it's possible that the cut will not finish and you will pull a strip down the culm, leaving an unattractive scar.
Sometimes you may want to cut the top portion of culms.   Topping culms can be accomplished to keep them away from overhead objects or just to shape the clump like a hedge.   You can cut them as short as you like as long as there are nodes below your cut that have branches and leaves.  Also, try to stick with the 1/3 rule (don't remove more than 1/3 of the total mass of the clump).   Each cut should be just ABOVE a node.  If you cut in the middle or just below a node, the section of culm left behind that above the node will turn tan and won't be clean and attractive-looking.  The bamboo won't be harmed – this is mostly an aesthetic tip.

For a more detailed illustration, please watch the video link here:
Bamboo Trimming Demo at Tropical Bamboo Nursery

Robert Saporito
Tropical Bamboo Nursery & Gardens