So my grandmother (Who although won't admit it, doesn't exactly have the greenest thumb ever.) bought a potted Bougainvillea about 1 to 2 years ago. About 4 6 months ago her and my grandfather decided to downsize and thinking this Bougainvillea was dead (Fall, it had dropped its leaves.) she removed it from the pot and left it there where it was. Today after it sitting there for long enough, decided it might make a good bonsai. I am certainly no expert and have never had any bonsai (Apart from one that I paid for in august. They left the regular nursery soil on the roots without loosening them at all and plopped it in a pot with some mostly organic bonsai soil. Root rot set in pretty quickly.) but I can grow and prune things well. The recovered Bougainvillea, after repotting in a smaller pot and removal of dead roots along with all dead branches, has a very nice slanted form to it. I know that time is the best thing for Nebari, but I would like to know if it would respond to wiring around the trunk or as I am already doing, removing the bracts/flowers? It would look very nice with a thicker trunk.

PS: I don't plan on doing anything major but basic pruning for at least a year so don't worry, I am not going to wire it tomorrow or anything. I know better than that.

Can you post pictures?

It is currently 10:30 here. Long after sundown. I will tomorrow when I get the chance.

MajorGoob wrote: They left the regular nursery soil on the roots without loosening them at all and plopped it in a pot with some mostly organic bonsai soil. Root rot set in pretty quickly.)

Don't blame the soil. Organic potting soil is absolutely no problem, if you water accordingly.

Bougainvill take a long time to close cuts, so do not let branches get too thick before trimming back. The wood is soft and rots very easily so it is important to get small wounds, that can heal over.

Depending on your local climate, it will take decades to get a proper trunk.

As the wood becomes stiff, bending when very young is the only real option.

This is the entire plant. It is not getting enough direct sunlight because of the MASSIVE storm here. That should pass in a day or so and it will be back to normal sunlight hours.
This is the trunk that I was talking about. I thought it might make a nice semi cascade or slanted style one day.

This is the large cut that I covered with petroleum jelly. I cut off a massive dead branch. I wish it had stayed alive because it would have made a nice addition to the apex of the tree which at the moment is quite lacking.

This is a very young tree, I start wiring as soon as the branches come out, when they placed the way you are looking for. The get brittle very easy and snap on you too. Go slow over several days to get results. I don't know what weather and climate you are in, but as soon you got horizontal branches grown you can cut leaves to trigger new branches too.

after 8 month

after 12 month

Should I wait until it roots and gets well established to wire it?

It looks to me that you can wire the tree, however you know best, because you know how long it has been in that pot.

This is the third day it has been potted in that particular pot.

Better let it be for a month or two then. The roots are like the branches, easy to snap. Just clipp what grows to big for what you are aiming for. I wire than repot them, but I am in the tropics they grow way faster here then anywhere else