Monopodial bamboo can easily become a nuisance by spreading far and wide.
Rhizome barriers are recommended by specialists, but over time the rhizomes will find their way either over or under the barrier, so we decided to trial the trenching method.
We dug a trench one foot wide and one foot deep all around the runner, and filled it with loose organic materials such as leaves and grass cuttings.
If there are no obstacles in the way, the rhizomes grow horizontally and are easily found in the trench.
Every six months we go through the trench to find the “escaping” rhizomes, cut them off close to the mother plant and take out the rhizome.
This has proven most efficient, we didn’t have any further spreading in over 4 years.