I was going to say that it would grow back sure. But that's for the client to find out especially after you tell them in writing that River reed or bamboo is persistent and grows back even after being mulched to shards. Give it a month and it'll be like the mulching never happened. Some clients like that are just like cash registers, willing to pay for the cut but not deal with the issue. However, as you said. The client just needs it knocked down in order to deal with it. So to bits it goes. Also, it's often easier to do bamboo like that by first clearing out a drop area then going "scoop and drop". Angle in to gather some using the brush tines while the cutter chips off the bottom. Pivot to get the gather to fall into the drop area, repeat to get a whole line down then go back to bust up the dropped section. Do that over and over side to side rather than straight in to have it fall over the top of you. Sometimes straight in is the only way, but ideally with bamboo like that, get it perpendicular to a drop area and then mulch it up. Think scythe cutting wheat more than grass cutting.
I was going to say that it would grow back sure. But that's for the client to find out especially after you tell them in writing that River reed or bamboo is persistent and grows back even after being mulched to shards. Give it a month and it'll be like the mulching never happened. Some clients like that are just like cash registers, willing to pay for the cut but not deal with the issue.
However, as you said. The client just needs it knocked down in order to deal with it. So to bits it goes.
Also, it's often easier to do bamboo like that by first clearing out a drop area then going "scoop and drop". Angle in to gather some using the brush tines while the cutter chips off the bottom. Pivot to get the gather to fall into the drop area, repeat to get a whole line down then go back to bust up the dropped section. Do that over and over side to side rather than straight in to have it fall over the top of you. Sometimes straight in is the only way, but ideally with bamboo like that, get it perpendicular to a drop area and then mulch it up. Think scythe cutting wheat more than grass cutting.