I looked online about and found this. I can’t see how it could survive in that small planter, even with pruning.

“Fast growing; forms large clumps 25 to 45 ft. tall. The large, dense habit of this Bamboo requires careful placement in the garden and will not be suitable for small, urban spaces.”

They want to form a FOREST in a wet, subtropical forest, not grow as bonsai in a desert. There have got to be better choices for you. There are clumpinig tropical species that may be more manageable as long as they get watered.

Ligustrum

Banana trees?

A clumping bamboo may be just the ticket. Some will grow to 20 feet and do well under your circumstances and condition. Discard ligustrum suggestion.

Maybe multiplex if not big enough for oldhamii?

Bougainvillea is another possibility.

Thanks Anne, but like Ligustrum, Bougainvillea doesn’t meet the height requirement

It can absolutely meet your requirement. I’m in the IE and see it often . Plus, it so colorful that it would become the focal point.

OK, I'm not understanding what you're trying to block out, Is that your house behind the wall? Are you wanting to block the windows so you can't see out? Or Is that your neighbor's house? Is that your patio? I don't see a driveway that you mention. Where is that in relation to everything? And you don't say how high this needs to be or how wide.

That is my neighbor’s garage. The wall separates our side patio from his garage. The picture shows how high and wide is needed…

First, while it looks very close to your concrete block wall, I'd hardly call your neighbor's garage an eyesore. It is just the side of a properly maintained garage painted a boring color. And unless the neighbors use the garage for a purpose other than to park their car and store stuff, privacy is not even really an issue either........I doubt they are hanging out in there staring at what you are doing in your backyard!!

Giant timber bamboo is overkill for this situation. You don't need anything that tall nor is it well suited to that confined a space. Something that will reach 8-10' will be more than adequate - pittosporum, podocarpus or other medium height prunable broadleaved evergreen hedging plant is a better choice. Even a smaller growing clumping bamboo, as previously mentioned.

The garage is not ‘properly maintained’ in fact. Rotting roof shingles have blown onto our patio in strong winds. Pittosporum and podocarpus are too slow growing (read the requirement for a relatively quick solution). And no, the garage is not used to park cars, but as a ‘man cave’ for MC friends. There is a side path that is frequently used so, yep, privacy is an issue.

Whatever. You ask for advice or suggestions and then summarily dismiss whatever you have been given.

It was made very clear on a previous and very similar thread you participated in that planting timber bamboo in a very confined concrete planter was not a good idea and why. Did that not sink in?

Not true. Acknowledged Anne Duke’s good idea of a different clumping bamboo. Also, nothing was made ‘very clear’ on the other thread, which featured opinions both for and against giant timber (and in a planter with two-thirds the depth, no less). Looking for opinions and guidance from informed contributors only please.

A tall bamboo will definitely work here with one drawback..it will get so thick in the box it will need thinning as the box fills up..…that…will be a big..and possibly dangerous project..we have a similar situation and even had to cut the tops off to avoid interfering with power lines..watering often is a chore… also cut bamboo stalks can do great harm if fallen upon or if you reach into a box with sharp cuts…not sure if there is even room for the root depth needed for such tall bamboo…if the planter has no bottom that may work better..as the height may be better supported by deeper roots..if you have a reliable nursery I would as for advice on possibilities more suited to your needs…

Our bamboo is in the ground but next to the pool…next to a concrete block ball…which limits how far the roots can spread or multiply therefore decreasing the need of thinning..in my experience clumping bamboo will never get tall enough for your purposes…and they have a shorter lifespan …

Next to a concrete block wall!🤷🏻‍♀️

Thanks btydrvn! All great points

Bougainvillea doesn’t ”meet the height requirement “ ??? 20’ to 30’ high (with support) not high enough? That’s how tall ours are at the entrance to our gated community. They do require lots of maintenance however.