Bonsai Nut
Nuttier than your average Nut
A short primer for those who are new to bonsai and are wondering how to evaluate trees at their local garden center for use as pre-bonsai material.
First, let's spend a little time on the Horticultural aspects. These include the following:
1) Species
2) Health
3) Care
Species - is this tree/plant a species that is popular for bonsai? Note that ANY tree/plant can have bonsai techniques applied to it to turn it into a bonsai. However, as a beginner, you are probably best off focusing on more popular species because (1) they have characteristics that make them appealing / easy to work with and (2) there is a lot of reference material available to help you with care and styling. A list of the easiest species (for beginners) would include junipers and elms, with other deciduous trees like maples, oaks, hornbeams, etc, topping the list. If you live in a tropical area, ficus are also very good. It is probably best for you to leave pines and other needle conifers alone until you feel comfortable with basic techniques on other tree species.
Health - make sure your tree is bursting with health. If you are buying it during the growing season, make sure that new growth is very apparent and profuse. It should not look limp, and no leaves or branches should look burnt or dried. Make sure there are no signs of injury, disease, or insect infestation.
Care - has the tree be well-cared for? Does it look recently repotted (with healthy roots) or does it look root-bound in its current container? Has it already been trimmed and shaped (even as a landscape tree) or has it been allowed to grow randomly?
Once you have decided on an appropriate species, and have located a healthy and well-cared-for plant, how should you evaluate it for potential? Here are a few additional criteria that can help.
It is easiest to think of a bonsai tree as a pyramid -- the lower you are on the tree the more difficult it is to change / influence something, while the higher you are on a tree, the easier it is to change something. Therefore when looking at a tree, you must always start at the soil and progress upwards - if a tree has poor roots and a poor trunk base, it will not be good quality starting material regardless of the condition of the rest of the tree.
Here are Esthetic aspects to consider (in priority order of importance):
1) Roots / base of trunk
2) Trunk
3) Branches
4) Style
Roots / base of trunk - look at the base of the tree and investigate the base of the trunk. You may even have to scratch the soil away from the base in order to see the upper roots where they intersect the trunk. What you are looking for is a strong base - multiple thick roots that join the base of the trunk on all sides like spokes of a wheel. The tree should look like it is 'grasping' the soil (giving it an appearance of strength and age). You do NOT want a tree that has one main root that goes straight down into the ground (as many landscape trees do), or a tree with one or two main roots on one side of the trunk, and no roots on the other.
Trunk - once you have found a tree with good roots, look at the trunk. You are looking for a strong, thick trunk with a strong, positive taper. What this means is a trunk that is shaped like a pyramid - thick at the bottom (the thicker the better) and tapering gradually to the top of the tree. You do not want a tree with an inverse taper - one that starts thin and gets thicker in the middle, or a tree with dramatic lumps in it that are substantially thicker than the trunk immediately below.
Branches - for a beginner bonsai you will want a lot of branches to chose from when styling your tree. Generally speaking the bottom 1/3 of the trunk of your bonsai will have no branches at all (so you may end up cutting off branches that are too low). The first branch of your bonsai (known as the "primary branch") is very important and should be located about 1/3 of the way up the trunk and should project forward from your bonsai at about a 30 degree angle (i.e. never toward the back, and never directly toward the side or the front). Once you have located your primary branch, you will want there to be a branch a little higher up on the trunk, on the other side of the trunk, ALSO pointing forward (known as the "secondary branch"). Next you will want a branch a little higher up, pointing to the rear of the tree ("back branch") and you will want the branches to continue to alternate as you work your way up the tree (i.e. left, right, back, left, right, back - assuming your primary branch was on the left side of the tree to begin with). The branches should get progressively smaller as you move up the tree, and the lower branches should hang lower (as if they have been pulled down with time) while the upper branches will gradually point more and more towards the perpendicular. Note that it is very rare to find a tree with perfect branches and branch placement - however the lower branches are most important and the higher up you go on the tree the easier it is to fix branch problems.
Style - I will only touch on this because styling a tree is a complicated subject that requires a lot of attention elsewhere. When first starting in bonsai, it is best to start with a tree that "suggests" a style to you. Probably the easiest bonsai style to design a tree for is "informal upright" where the tree leans slightly to one side and the apex of the tree is located off-center. Many nursery trees will be well-suited to informal upright styling - they will be upright without being perfectly so (i.e. they won't look Christmas Tree perfectly straight and tapered). Another style popular with beginners is cascade style (either semi-cascade or full-cascade) especially if you are working with junipers that have a natural slumped-over or ground-hugging growth pattern.
Hopefully this article will help beginners on their next trip to the nursery. It should be noted that as you become more advanced you can break MANY of the "rules" listed here - even taking a tree that seems ready-made for one style and dramatically reworking it so that it fits with your vision of a tree in an entirely different style. But it is best to start by mastering the fundamentals - and most of the fundamentals listed in this article will still be true for most of your trees in the future.
First, let's spend a little time on the Horticultural aspects. These include the following:
1) Species
2) Health
3) Care
Species - is this tree/plant a species that is popular for bonsai? Note that ANY tree/plant can have bonsai techniques applied to it to turn it into a bonsai. However, as a beginner, you are probably best off focusing on more popular species because (1) they have characteristics that make them appealing / easy to work with and (2) there is a lot of reference material available to help you with care and styling. A list of the easiest species (for beginners) would include junipers and elms, with other deciduous trees like maples, oaks, hornbeams, etc, topping the list. If you live in a tropical area, ficus are also very good. It is probably best for you to leave pines and other needle conifers alone until you feel comfortable with basic techniques on other tree species.
Health - make sure your tree is bursting with health. If you are buying it during the growing season, make sure that new growth is very apparent and profuse. It should not look limp, and no leaves or branches should look burnt or dried. Make sure there are no signs of injury, disease, or insect infestation.
Care - has the tree be well-cared for? Does it look recently repotted (with healthy roots) or does it look root-bound in its current container? Has it already been trimmed and shaped (even as a landscape tree) or has it been allowed to grow randomly?
Once you have decided on an appropriate species, and have located a healthy and well-cared-for plant, how should you evaluate it for potential? Here are a few additional criteria that can help.
It is easiest to think of a bonsai tree as a pyramid -- the lower you are on the tree the more difficult it is to change / influence something, while the higher you are on a tree, the easier it is to change something. Therefore when looking at a tree, you must always start at the soil and progress upwards - if a tree has poor roots and a poor trunk base, it will not be good quality starting material regardless of the condition of the rest of the tree.
Here are Esthetic aspects to consider (in priority order of importance):
1) Roots / base of trunk
2) Trunk
3) Branches
4) Style
Roots / base of trunk - look at the base of the tree and investigate the base of the trunk. You may even have to scratch the soil away from the base in order to see the upper roots where they intersect the trunk. What you are looking for is a strong base - multiple thick roots that join the base of the trunk on all sides like spokes of a wheel. The tree should look like it is 'grasping' the soil (giving it an appearance of strength and age). You do NOT want a tree that has one main root that goes straight down into the ground (as many landscape trees do), or a tree with one or two main roots on one side of the trunk, and no roots on the other.
Trunk - once you have found a tree with good roots, look at the trunk. You are looking for a strong, thick trunk with a strong, positive taper. What this means is a trunk that is shaped like a pyramid - thick at the bottom (the thicker the better) and tapering gradually to the top of the tree. You do not want a tree with an inverse taper - one that starts thin and gets thicker in the middle, or a tree with dramatic lumps in it that are substantially thicker than the trunk immediately below.
Branches - for a beginner bonsai you will want a lot of branches to chose from when styling your tree. Generally speaking the bottom 1/3 of the trunk of your bonsai will have no branches at all (so you may end up cutting off branches that are too low). The first branch of your bonsai (known as the "primary branch") is very important and should be located about 1/3 of the way up the trunk and should project forward from your bonsai at about a 30 degree angle (i.e. never toward the back, and never directly toward the side or the front). Once you have located your primary branch, you will want there to be a branch a little higher up on the trunk, on the other side of the trunk, ALSO pointing forward (known as the "secondary branch"). Next you will want a branch a little higher up, pointing to the rear of the tree ("back branch") and you will want the branches to continue to alternate as you work your way up the tree (i.e. left, right, back, left, right, back - assuming your primary branch was on the left side of the tree to begin with). The branches should get progressively smaller as you move up the tree, and the lower branches should hang lower (as if they have been pulled down with time) while the upper branches will gradually point more and more towards the perpendicular. Note that it is very rare to find a tree with perfect branches and branch placement - however the lower branches are most important and the higher up you go on the tree the easier it is to fix branch problems.
Style - I will only touch on this because styling a tree is a complicated subject that requires a lot of attention elsewhere. When first starting in bonsai, it is best to start with a tree that "suggests" a style to you. Probably the easiest bonsai style to design a tree for is "informal upright" where the tree leans slightly to one side and the apex of the tree is located off-center. Many nursery trees will be well-suited to informal upright styling - they will be upright without being perfectly so (i.e. they won't look Christmas Tree perfectly straight and tapered). Another style popular with beginners is cascade style (either semi-cascade or full-cascade) especially if you are working with junipers that have a natural slumped-over or ground-hugging growth pattern.
Hopefully this article will help beginners on their next trip to the nursery. It should be noted that as you become more advanced you can break MANY of the "rules" listed here - even taking a tree that seems ready-made for one style and dramatically reworking it so that it fits with your vision of a tree in an entirely different style. But it is best to start by mastering the fundamentals - and most of the fundamentals listed in this article will still be true for most of your trees in the future.
However re-reading it today I find it is so short as to be almost unusable 
