Oak sapling in pot is not branching

Question

I moved a small oak sapling to an indoor pot last year and intend to keep it as a bonsai project, the tree seems generally healthy and had one growth this season allready (it didnt lose all its leaves in winter though) (as you can see in the picture). I allready repotted it from a smaller container once and removed some of the roots and the main root when doing that (in hindsight I am not sure that was the best thing to do).

I am wondering if i can do something to make it branch out, as the tree is currently just growing vertically. Any care tips are also very welcome!

Thanks a lot, Thomas

Answer 1

Bonsai projects are great! I have many running at the moment too. Also some oak, but mine are branching already... I see a few problems here. First of all, this tree (plant) needs to grow outdoors, not indoors. It needs sun, rain, and wind, but most important cold winters as well. It needs to lose its leaves in winter. Branching occurs very often in spring right after winter. So my advice is to give it its natural environment back, put and keep it outdoors. But let it slowly adjust (acclimate) to full sunlight first, by giving it a little bit more sunlight each day.

Second advice, is to let the tree first grow bigger and bigger (without the root trimming). It takes about 7 years before the stem is thick enough for bonsai. Then after these 7 years, you shape it and put it in a real bonsai container.

Good luck with your project!

Answer 2

Good advice from @benn.

The #1 killer of bonsais is having them indoors. The danger of outdoor bonsais is letting them go dry. This can happen in the summer (duh!) but also in the winter if there is a strong wind and freezing temperatures. The wind dries the foliage, but the soil is frozen so the tree can't replace the water.

This may not be a good specimen to put your effort into because of the lack of lower branches. There is a lot you can do to modify a bonsai, but you can't make them sprout new lower branches. New lower branches can be done with grafting, but that's a whole new challenge. When I chose a new bonsai project, it almost wholely on the basis of lower limb architecture because you are stuck with that. Traditional esthetics put value on branches which alternate side-to-side up the trunk.