you can buy a special bamboo membrane for stopping them growing further than you want or get a large strong bucket/dustbin .the old black ones with nylon in are best.cut the bottem out and bury the whole container leaving just an inch or so above ground.bamboo will burst out of pots eventualy but bye burying them you have the soil around the bucket to stop this.on top of that buckets/old dustbins bye nature slope outwards so any new shoots tend to be sent upwards wear you can cut them of or put them in a pot and sell them.just some good topsoil is plenty good enough soil as they are very hardy will do.i myself cut out all the shoots that wernt the thickness i wanted but you can just cut the bamboo right down as it will put more into rooting.

you can buy a special bamboo membrane from bamboo suppliers thats 60cm wide and baught in as long a lengths as you want .you can bury this round your inherited invasive bamboo to stop it going further to if you want.

You don't need to do anything, but as you want it in a pot, if the rootball is large, say more than 8 or 10inches across, I'd be inclined to cut it in half (with a breadknife, most efficient, lol) and pot up the two sections separately. If its larger than that, you could make three sections.

ofcourse you dont have to make it a bigger plant and just keep splitting it as it bursts out of each tub you put it in and maybe sell them of.you dont have to dress or cut out some stems either .its just if you wanted a bigger plant that was not in a pot as such and wanted it to look more natural without spreading everywear .its just an option . me and a friend baught a yellow caned bamboo of the same type from the same place urban jungle of norwich . very good for something out of the ordinary bye the way if you live close .anyway i planted mine at the same time as his .he just planted his and apart from watering did nothing else .i dressed my one up to about 3 foot up ie took all the leaves off of it.i also took out all the shoots that wornt as thick as i wanted .this actualy left 4 thickish shoots in the end . i also used this membrane which has worked a treat .he left dressing and cutting out the thinner canes .he like me had about 30 canes from barley thicker than grass to about 4-5 half inch thick ones .now 2 years later mine has about 25 inch thick beautifull stems and they are now about 18` tall .his has hundreds but none are taller than about 7 foot tall from when he got the plant.its also popping up all over his garden .its just preferance realy but bamboo is right in so much as you can just keep chopping it up and repotting .