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Indoor Bonsai

Among bonsai professionals and amateur enthusiasts alike this is considered a controversial topic. It's said that it simply can't be done.

Professional high quality bonsai trees are grown, developed and kept outdoors at all times, with very few exceptions.

Depending on where you are located some outdoor trees may be taken indoors for winter storage and they of course survive short indoors exhibitions but keeping a tree indoors for an extended period of time will inevitably kill it.

With this out of the way. Here are my thoughts on this topic after experimenting with this impossible task for a number of years.

Obviously you can't just take any old tree and put it indoors in a tiny pot and expect it to survive. They key here is to choose a suitable species. Think potted houseplants. Tropicals and subtropicals.

What has worked best for me is Ficus microcarpa sometimes sold as "ginseng" ficus. It can take a lot torture, is very forgiving and is a fast grower. The leaves often tends to be a too large to make a good Shohin-sized bonsai but sometimes yo get lucky and can reduce the leaf size.

You can buy a cheap ugly specimen from wherever. Make sure it survives the transition from the store to your home. This means repotting it into good bonsai soil and fertilizing it. When it looks healthy you can brutally reduce the root mass i.e. removing the horrendous tube-like roots and start working towards a nice radial horizontal root spread. This will take a couple of years. If the trunk is ugly you can also cut it back and work towards a tapered look. Otherwise just let it grow. This is a slow process and don't get your hopes up. The initial reduction of the root mass may kill the plant.

When you are happy with the roots and trunk it is finally time to start working on the upper parts of the tree. This is the fun part. Cut off unnecessary branches, cut back to induce backbudding and further ramification. Ficus microcarpa responds well to wiring and after a lot of time, effort and some luck in about 10-15 years you will have something reassembling a Bonsai.

The second best alternative in my opinion is Portulacaria afra. It's a fast grower with tiny leaves and easy to take care for. It can make a pretty good indoor bonsai. The biggest problem is that branches are brittle and can easily break when you try to position them using wire so when possible I suggest shaping the plant via the clip and grow method but this can also be troublesome since the branches tend to grow in very straight angles making it look unnatural and un-tree-like. Nevertheless, this is a good candidate for creating indoor bonsai of the smaller variety.

Bougainvillea is also worth mentioning. I've had mine for many years and it seems to enjoy living indoor which was something I didn't expect. It's a very slow grower so I suggest getting one with a suitable trunk. It's easy to wire and the leaves reduces well. The flowers are beautiful.

Ficus benjamina. I've had mixed results with this one. The leaves are smaller than on its cousin microcarpa and it tends to look more tree-like but they tend to die on me for no apparent reason. For me Ulmus parvifolia, commonly known as the Chinese elm, also falls into this category. Very nice in all respects but out of nowhere they die.

Generally you get at most two windows per year to apply bonsai techniques to your indoor bonsai. The rest of the year you have to focus on their survival.

If you have the option to have your bonsai outdoors during late spring, and late autumn for god sake bring them out.

  • Don't expect great results. Your attempts at indoor bonsai's will never turn out like the stunning trees you see on youtube or instagram. In the best case they will look OK but they will never be able to compete with real outdoor bonsai.

  • It will take a lot of time. Even fast growers grow slowly. You should think in terms of 5 or 10 years when dealing with these plants.

  • It is very hard to achieve good ramification and the leaves will always be a little too big.

  • Don't expect trunks to get any thicker indoors.

  • Defoliation is most often a death sentence to your tree.

  • Think twice about doing larger operations on your trees. While being tolerant they can also be very sensitive to, for example, major root work.

  • Always expect sudden death. Many of your trees will die for no apparent reason. Get used to it. The solution to this is to get many trees and hope that some of them will survive.

  • Grafting techniques doesn't seem to work indoors.

  • Consider investing in an additional light source for your trees. Especially if live in a country with a long and dark winter.

  • Let them rest during autumn to mid-spring. Just water and fertilize. They have enough trouble surviving without you fiddling with them.

  • If the plant works as a houseplant it might work as a bonsai. Your your imagination.

  • Don't bother developing Bonsai from scratch, meaning from seed or very small cuttings. It simply takes too long. Start "big" and reduce.

  • The leaf size will probably always be a bit too large and out of proportion. Leaf size reducing techniques doesn't work as well indoors.

You can actually have indoor bonsai and make them look OK. But it's a long and challenging process filled disappointments along the way. When my best tree died on me I wanted to cry. In short, it can be done, with mediocre results at best. But if you are up for a challenge and is obnoxious and very patient, go for it.