A Bonsai can be created in a couple of hours from suitable material provided the whole plant is growing healthily. Certainly the basic structure can be established quickly even if it takes a couple of years for it to fill out. On the other hand, you may need longer if you are starting with seedlings.
A Bonsai can be tiny, no more than a couple of inches tall. These are classed as mame (mah-may) or shohin (show-heen) which translate as finger and palm Bonsai, a description of how you can hold them. A typical Bonsai is more likely to be a foot tall (Chuhin). There are larger sizes which can be 1+ metres tall. As the trees get larger, so the detail increases as does their longevity. A shohin will struggle beyond 15 years, larger ones are recorded over several hundred years.
Apart from the fact that collected material is difficult to age, imported material
often has an exaggerated age. Longevity is a valued characteristic in the Orient
and older trees attract higher prices...
Ignore the age, look at the tree and appreciate it for what it is. We can only get a true age if we cut it across the base of the trunk and count the rings and are you going to do that?
On the contrary; keeping a tree indoors is one of the quicker ways to kill a tree. Unfortunately, most Bonsai are seen in an exhibition environment - indoors. This placement may be fine for a day or two, after that it it detrimental. Trees like good light levels, plenty of moisture and cool temperatures. Indoors it is usually too dark, too dry and too warm. Plants which favour dry and warm conditions are 'mediterranean' types of plant but even then they need sufficient light.
A conservatory may be OK for overwintering tender species, but outdoors is generally best..
Trees originate from the outdoors, so keep them in the environment they prefer.
We sadly see too many trees brought for advice which are brown, dry and long beyond resurrection.
There is nothing special about the plants we use or the seeds they come from. The same tree seeds will produce trees or bonsai depending on how they are grown.
The key is to select species which best suit the Bonsai process and preferably have small branches and leaves (a palmatum maple is better than a sycamore).
In Japan the most popular species are Pines, Maples and Juniper. In Britain we also use Hawthorn, Yew, Field Maple, Elm, Beech, Hornbeam and Lonicera amongst many others.
An excellent guide: if it makes a good hedge it will probably make a good Bonsai.
It is far better to allow the tree to make growth before reshaping from time to time. Good pruning will encourage finer growth, too much will weaken the tree.
The best Bonsai are collected from the wild ("yamidori"). These have shapes different from those developed with specific designs in mind. The "faults" in wild trees become the characterisitcs which elevate them above the ordinary.
Trees grown entirely in a pot tend to have thin trunks and take much longer to achieve the desired effect. The small Shohin style are better produced from seedlings though as the fine structure have to be developed early.
The best sequence is to start the tree in open ground developing the trunk shape. Transfer to a large box to develop radial, fine roots and basic branches before putting into a Bonsai pot for refinement.
This is where you will find more opinions than anywhere else. The soils some Bonsai are potted in leave much to be desired.
The main requirements are to satisfy a tree living in a small pot. The soil needs to retain water and nutrients without becoming waterlogged. It needs air voids to allow the roots to breath and the soil provides an anchor for the tree - not much, eh?
Most Bonsai enthusiasts develop their own soil mixes for various trees. In general, a test of a good soil mix is to grip a moist handful of soil. If it remains in a lump it will damage if not kill the tree. The handful should crumble, hence the Bonsai is forced to bind the soil with its roots.
Pines are best in a soil which has a high proportion of sharp grit whilst deciduous trees are better with no more than about 50% of a rounder grit. Peat is poor because it dries and is difficult to re-wet; save the environment and use peat-free composts. Some John Innes loam based composts can result in airless soils; this is because they contain a lot of fine particles. If necessary sieve a dried soil to remove the fine stuff.
Imported soil components are available, but locally sourced soil parts will suffice.
You probably have - and so have we. A single page is too short to cover everything. Like many tasks, there is more than one way to achieve a result. If you want to learn more, add to the discussion or improve your Bonsai, join in, challenge yourself and us.