I'm not sure exactly what size plastic pond tub you have or how deep it is, but I would think it will fail at some point. Those that I have seen are not thick enough and the bamboo will puncher and grow right through it. Also, if the sides/walls are not at least 3 foot deep, the rhizomes will likely grow underneath it and eventually spread out.

The best way to prevent spreading is by rhizome pruning which needs to be done at least twice a year. Kudzu can explain this process better. Rhizome pruning and a barrier will ensure that your bamboo does not spread beyond your designated area, but a barrier alone, of any kind, usually does not work here, where running bamboo spreads like wildfire.

Keep us posted on how yours works for you.

Well as for the bamboo puncturing through the tub, you can just stack 2-3 tubs on each other for more thickness(make sure to cut off bottom before stacking) and deepness to an extent(more stacked tubs means a couple inches deeper). It'll be more expensive since you gotta buy more tubs but if it means that it'll be thick enough that the bamboo won't stab through it then I think its worth it.

And well I pointed out the tub strategy because its less maintenance and you don't have to keep pruning rhizomes every year. And the exact variety I am currently interested in growing is semiarundinaria fastuosa.

I don't see any advantage to using a pond liner over an approved bamboo barrier. For one, pond liners of a size suited for bamboo growth with that depth are difficult to find and expensive. And no more likely to restrain an aggressive running bamboo than would be the barrier. FWIW, if the barrier is installed properly and with a sufficient overlap at any joints, it should work perfectly well for restraint. That is what is recommended and sold widely here and I have not seen it to be an issue. But you can't just install a barrier - or a pond liner - plant a running bamboo and forget about it. Root/rhizome pruning and barrier jumping will always be possibilities.

But with the tub there is no opening on the sides whereas a barrier would. So isn't that one advantage?

Albert, because they're not bog plants...

"But with the tub there is no opening on the sides whereas a barrier would. So isn't that one advantage?"

Not really :-) If the barrier is installed properly, there should be a 12-18" overlap and with the proper attachment hardware, there will be just a strong, secure joint.....not an 'opening'.

I installed six barriers all about 9' X 27' and all failed within a few years. I admit I probably did not have the top of the barriers wide enough at the tops compared to the lower part, but they failed, none-the-less. I will say that large runners are very aggressive here in the south and I'm sure that played a part in the escaped rhizomes. Soil here is sandy loam and the rhizome punctured holes right through the sides of the barriers. I now rhizome prune to keep the remaining bamboos in check.

Probally dumb ? But would plastic or steel bathtubs work and if so would you need more holes for drainage why would drainage be needed at

I know many who grow running bamboo in galvanized metal stock troughs. A pretty secure containment system!! And yes, you need drainage holes. Everything but water plants need drain holes and good drainage if grown in a container.

Galvanized metal troughs work perfectly...until the bamboo inevitably gets rootbound and starts dying. Then you have a large container of sickly and dead bamboo that weighs hundreds, perhaps thousands, of pounds. Because of the dense woody structure of the rhizomes, it will be impossible to get the plant out of the trough without destroying the container. It will be nice for a number of years, but just be prepared to deal with the predictable consequences.

I have a friend who went even further. He bought a large, steel, cylindrical tank for containment, and buried it in his backyard. Fast forward several years and he then had a container of roots and dirt and dead bamboo that weighed so much that there was no way he could excavate around it and lift it out of the ground. So now he has a 2' diameter cylindrical area in his yard where nothing will grow.