Is it allowed? I read through the rules and find nothing that speaks against it. It is not destroying a plant or digging the earth as I understood these rules.
The damaging of a plant doesn’t mean it kills the plant. Any form of cutting would count. So being the sole caretaker wouldn’t be possible.
Digging in soil that is in a pot isn’t necessarily a problem.
Watering a bonsai shouldn’t be an issue, although there may be some commentarial issue with it.
Thank you for the clarification.