Choosing a Tree
There are a few different sources for obtaining a bonsai, which are described below. But first you need to know what to look for in a potential bonsai.
What to look for
Trunk & Nebari (surface root spread)
Ideally the tree will have a thick, tapered trunk with interesting movement (curves, twists) and flares out at the base into a uniform arrangement of surface roots radiating outwards. These factors are most critical because they are difficult, if not impossible, to change.
Health, disease, infestations
The leaf colour can indicate if there are any nutrient deficiencies. Dead shoots are probably due to a lack of light, but whole dead branches may indicate a more serious problem. Also check the foliage for signs of pests or fungal disease. However, note that pines will have a white fluffy substance around their roots - this is not mould and does not indicate poor health. It is mycorrhiza, a fungus that is vital to the health of the tree in helping digest nutrients, and should be kept when repotting.
Examine the internal branch structure of the tree, as this is an important starting point for creating your bonsai. Branches can be repositioned or new ones encouraged to grow, but working with what is already there is easiest. The tree will indicate what style can be best achieved; but in general look for evenly spaced branches coming out from all sides of the tree and good ramification (division of the branches).
Knowing how to care for the type of tree is essential - indoors or outdoors, shade or sunny, how much water it needs, best times of the year to feed, prune and repot.
Where to get a bonsai
Grow one from seed
This is a nice idea, and the tree would have been created by you from scratch, but who has time to wait 20 to 100 years? Even cuttings take time to grow into something useable. By all means have "growing-on" trees in your collection, but to get some practice in, try one of the other sources.
Buy a ready-made one from a garden centre
Many garden centres sell "bonsai" which are often advertised as "starter trees" and planted in a shiny blue pot. Take care when choosing this option, as these trees are often mass produced and imported from China. They are often struggling healthwise and planted in poor soil, so if you do buy one, it will need a lot of care to ensure it survives. But this source is often what first sparks a person's interest in bonsai.
Buy a ready-made one from a bonsai expo
These are usually of a slightly better quality as they are heading for the specific bonsai market, but still usually mass produced in China for the western market. However, there is a wide variety of choice at these events and often hidden gems to be found.
Create one from nursery stock
You can buy nursery shrubs or trees of varying ages and then put your bonsai techniques into practice to restyle the tree and begin to train it to look like a bonsai.
We sometimes have meetings where this is the basis for a challenge. This year at our April meeting we are hosting "I'm a Bonsai - Get me out of here!", where members draw lots to purchase a random nursery stock tree and have the remainder of the evening to re-style it as they wish.
Visit a bonsai club
We often have members selling their trees at our monthly meetings and this year we are holding an auction which will feature a variety of trees, tools and other bonsai-related items (16th May, see programme).
Collect a tree from the wild
Collected material is known as yamadori and has often been growing there for some time, often making it quite old and interesting. Maybe some old hedgerow or a tree in your garden that you no longer want. Some are even collected from forests, but please make sure you have permission.
Digging up old trees requires knowledge and experience in order to ensure the tree's survival. You should therefore think carefully before doing this if you do not have the necessary skills.