Article 12 – ‘Selecting material for bonsai part II’

Selecting material for bonsai part II

Air layering – although not really a grafting method is a common practice in obtaining potential bonsai material that has some substantial growth, but again much depends on the species. The illustration below shows an old deciduous shrub, which may look as potential bonsai material, but has problems for example. Poor branch displacement and reverse taper at the base of the trunk. Nonetheless, a possible candidate is the lower branch on the right. The following illustrations show the air-layering process.

Air layering 1

Air layering 2

Air layering 3

Air layering 4

Collecting from the Wild – causes arguments on both sides. Those in favour may argue that species they require can not be found at nurseries or bonsai outlets furthermore, seedlings and cuttings will take many years before reaching maturity.

Here are some thoughts on the issue. In some countries where timber harvesting is part of their economy, vast areas of trees are cut and removed. (Although the land is replanted) These areas will have many trees often damaged by forest machinery, so some horticulturists will ‘rescue’ and remove them and of course permission will have been obtained.

In Scandinavia all roads with the exception of some forest tracks have huge ditches either side, this is the dumping area for the huge amounts of snow and ice, which is cleared from the roads by the snow plough during winter time. When spring comes and the snow has gone, a short excursion along these ditches reveal hundreds of trees bent and twisted during their months of icy confinement.

Such an environment considered as a bonsai enthusiast’s Smörgesboard, will be cut down by giant lawn mowers to keep the ditches free and devoid of vegetation. So the question to those opposed to collecting from the wild is; is it unethical to rescue or harvest these trees (Providing permission has been granted) when they will inevitably be destroyed?

But the biggest opposition to collecting material from the wild comes not only from opponents, but from bonsai enthusiasts as well. Because the novice has no idea in the slightest of how to harvest a wild tree and ends up killing it rather than leaving it alone. For the professional bonsai enthusiast this is probably the most bitter pill to swallow as unprofessional conduct not only harms our reputation, but tarnishes the name of this ancient art.

Collecting material a personal perspective – most of the trees in my collection have come from waste sites and areas designated for development. Other sources available are from home owners bored with seeing the same view are redesigning their gardens. Thus shrubs and trees of different species destined for the scrap heap can usually be had for a polite word. All one has to do is dig them up and cart them away.

Nonetheless, countless hours have been spent scouring various landscapes (Mountains, forests and swamps) all of which have given not only great pleasure, but also a learning curve in the way that nature reveals itself.

My directive when looking for bonsai material from any source is first to obtain permission from the landowner to collect.

If a potential candidate is found, it has to be inspected. Examine the trunk down at the base to make sure there is no reverse taper, look for signs of disease and check the foliage condition. Next inspect the terrain what does it consist of, if there are a lot of large rocks in situ, these will be a problem. Because the tree’s root system may have penetrated underneath and in most cases are inaccessible and digging out rocks can damage the root system.

However, if all seems fine up to this point, the next step is to make a sketch of the candidate and in so doing one is able to see by making a few alterations if there is any possibility of it becoming a potential bonsai. If there are any doubts, then walk away. This method of approach means that (a) you have not disturbed the tree which is most important and (b) you have saved yourself from a lot of hard unnecessary work.

But, if all the signs are positive the next part of the operation is to measure the height of the tree as this will give a good indication of its root area. For example, if the tree’s height is 80cm then the root system will spread out in all directions at approximately this length, if not more. This is not an accurate measurement it is an approximation because all trees are different and much depends on the terrain that it is growing in.

To explain further, a few years ago I found an old weather beaten and scarred Juniper, Juniperus communis its characteristics had all the hallmarks for a potential bonsai. But on inspection it was discovered that this was only one branch, further investigation showed that this particular tree had been growing over rocky terrain and that it’s main root system was over 2 metres away. Although the branch in question had produced roots, these were insufficient to support growth and health, so it was left alone.

One method of collecting specimens if they indicate bonsai potential is to investigate the root system and to ascertain, which roots can be cut and which roots to leave. When the operation has been carried out, the soil is carefully replaced and the tree is left to recover. The collector then returns the following year and checks for new root growth and if possible, repeats the process on the other roots that were untouched. The collector returns the next year, inspects the root system and if all is well removes the tree.

Some may argue that this method is ‘long-winded’ – taking too much time. But the most important factor when collecting from the wild is to ensure that if a potential candidate is found, one has to retrieve of much of the root system as possible otherwise the chances are it will not survive. And this is the problem that the novice bonsai enthusiast fails to understand.

When to walk away – my place of residence is surrounded by forests and in one particular area is a pine Pinus sylvestris L. estimated to be over 200 years old. Its style is a mixture of Sekijoju or ‘root over rock’ and Bunjin-gi – Literati and would be classified as Imperial due to its height approximately 200cm. The tree during its life has suffered many traumatic experiences due to the evidence of natural Shari and Jin, and its trunk is gnarled and twisted. If collected such a specimen would be highly prized among bonsai enthusiasts, but this is one tree to be left alone. Partly due to the cost of excavation and partly due to the amount of manpower required. But more importantly, the health and life of the tree.

Another example of when to walk away concerns yet another pine Pinus sylvestris L. 149cm and classified as Hachi-Uye. It can be considered as a Yamadori bonsai due to its characteristic appearance and age estimated 130 years. But it is growing among large granite boulders requiring substantial manpower and tools to remove. Furthermore, it’s root system will have traveled far penetrating below and through the crevices of the surrounding rocks and thus, would be extremely difficult to locate and retrieve.

During my travels there have been many instances where similar examples have been located and no doubt there will be many more. But, I prefer to leave them where they are, left undisturbed.

Equipment needed for collecting bonsai material – I have been asked this question on previous occasions and as stated earlier, most of the trees in my collection have come from waste sites and land designated for development. For example, old industrial areas where the building/s have been removed leaving just the foundations. And if left untouched, seeds blown by the wind will have rooted in the cracks and crevices and developed into trees. To remove the masonry, a pick axe, long metal bar, heavy hammer and chisels are advisable and the work is quite intense. Of course one still needs the standard tools a spade, fork, trowel, 2 or 3-pronged raking fork, geologists hammer and shears. Other equipment includes a hand saw, plastic bags, cord, tape, cling-film (plastic wrap) water for the specimen/s and most important of all a good pair of gloves.

But much depends on the terrain for example, going over a cliff edge and climbing down as I often did requires a good rope and harness. Only taking the bear minimum of tools because of the weight factor. Some collectors have a winch or two in their kit to aid excavation and to see this method in operation visit youtube where an assortment of examples can be seen.

But in reality selecting tools for excavation is down to common sense, because the collector will know the type of terrain and what is required. But the most important factor to remember is to retain as much of the root ball as possible so that the tree has a good chance of survival. One last item to remember is to count the number of tools in your rucksack when you reach a site and when you are about to leave, count them again…. Yes we have all done it – leaving tools behind.

If readers and/or followers of this blog have comments or questions of what has been written so far, then please feel free to do so and I will respond. Until the next post – bonsai tools, BW, N.

Article 11 – ‘Selecting material for bonsai part I’

Selecting material for bonsai part I

There are a number of ways material for bonsai can be acquired and the following sources can be a good way to start.

  • Reputable dealers

  • Nurseries or garden centres

  • Seed and cuttings

  • Grafting

Before we discuss the above sources, it might be advisable to ask yourself the question –

What sort of tree am I looking for?

To assist in making the decision the following factors may be of use.

  • What is the climate zone – taiga, alpine, temperate or mediterranean

  • From where does the species of tree/plant originate – native or foreign

  • What environment will the tree/plant be kept in – inside or outside

  • If inside how much natural light will the tree/plant receive

  • If outside what protection can be given to the tree/plant in cold temperatures

  • What are the characteristics of the tree/plant – prolific or slow growing

  • Do I have the space and the time to care for it

These questions are important, because they are related to the health and development of a potential bonsai. For those wanting trees/plants destined for indoor propagation, there are an assortment of species available for example, Ficus of which there are many varieties. Alternatively, those with a desire for hardy coniferous and northern European deciduous species, these have to remain outside because they require a period of dormancy, (Autumn to spring) and may need additional protection during the winter months.

Reputable dealers – are able to offer a wide variety of potential bonsai to customers, but they can be expensive due to their stage of development. Such material can be had by visiting the grower’s establishment and selecting a specimen. Arguably this is the best approach, because not only does it allow you to view what is on offer, the grower will be able to provide information and advice on how to care for the tree/plant.

But not everyone is able to make such visits because of invalidity, distance and mobility therefore, they resort to ‘on-line’ purchasing.

However, not having gone down this route to obtain specimens, obvious questions abound. For example, a tree/plant may have the appearance of health and vigour. But it has to travel from one destination to another and how it fares during this transition remains to be seen. Arguably much has to do with packaging and transport and even if well protected there is still the danger of irreparable damage.

Evidence of this comes from visiting horticulture establishments and witnessing the conditions trees and other plants have had to endure during transport, then being unpacked ready for sale. However, there are those having had successful ‘on-line’ purchases will state that this scepticism is unfounded. Because growers need to maintain good relationship with their buyers; hence their stock is always in good condition. But we are not discussing house or garden plants, we are discussing bonsai that can be expensive. ‘On-line’ purchasing is a risk and one has to ask many questions before making the final decision.

Nurseries or garden centres – can be seen as a relatively good source for potential bonsai material however, it pays to examine the specimen closely. First examine the base of the trunk to determine any nebari (Surface root system) and to check how long it has been in it’s container. The obvious signs are a coating of moss on the top of the soil and roots protruding from the base. These are indications that the specimen is established in the container, further proof can be had by easing the plant gently out to further inspect the root ball. The next step is to examine the trunk for movement meaning does the trunk curve or lean to one side, and what of the branch configuration – in other words does the specimen have the potential to become a bonsai.

In addition, it pays to be diligent when examining material, because one can find lots of problems. Damaged branches, leaf yellowing caused by either over or under watering and disease. Long thin shoots with nodes spaced too far apart caused by insufficient natural light that are of little use in a potential design. A partially decayed root ball will often be a thick tangled mass that has wound itself around the container searching for nutrients that are not there; and with trees in this condition it is best to walk away.

Nonetheless, specimens with potential can be found relatively cheaply. One I found a Forsythia a member of the Oleaceae (olive family) with a good strong weathered trunk has the potential to become a Mame bonsai in a few years time. Another example was located in a supermarket of all places, the plant a Ficus microcarpa ginseng had no real potential as a bonsai. But was ideal for cuttings that when rooted could be given to bonsai students to practice on. Therefore, it does pay to browse around to see what is available.

Seed and cuttings – can be purchased from reputable distributors, but it is advisable to ask whether they have undergone the stratification period. Stratification is the process of treating stored or collected seeds prior to sowing to simulate natural winter conditions, which the a seed must endure before germination. Some seed species undergo an embryonic dormancy phase, and generally will not sprout until this dormancy is broken. The time taken to stratify seeds depends on species and conditions; though in many cases two months is sufficient. If collected seeds need stratification, they can be put in a plastic bag and stored in the refrigerator for this period of time.

Of course some species of tree especially fruit bearing do not require stratification and can be sown after the fruit has been consumed such varieties are citrus species family Rutaceae, mango genus Mangifera, avacado genus persea and pomegranate Punica granatum. However, not all seeds will germinate for example, certain apple varieties Malus, peach Prunus persica and cherry Prunus cerasus have problems. Arguably because the fruit was picked long before the much needed information required for germination could be passed from the parent plant; thus the seeds are sterile. Nonetheless, if fruiting varieties are favoured, the best time to collect their seeds is when the fruit has fallen from the tree.

Growing from seed is often rewarding because, it affords the bonsai artist complete freedom in shaping the tree’s design. But the downside of growing from seed is the length of time the plant needs to grow to an acceptable size for a bonsai potential, which can take a minimum of 5 years. Although much depends on the species of tree/plant and its characteristics. Moreover, such young specimens need to be grown in preferably the ground or large containers to allow for root run and trunk development. Because a tree/plant with a trunk as thick as a pencil will never gain any trunk girth if it is in a small container.

Cuttings also known as striking or cloning, is a technique for vegetatively (asexually) propagating plants. In which a piece of the stem or root of the source plant is placed in a suitable medium such as moist soils, a potting mix, coir, rock wool or water. The cutting produces new roots and stems and thus becomes a new plant independent of the parent.

Cuttings can be taken from soft green or semi-ripe wood and hard wood which has specific differences in practice. For favourable outcomes timing, size, location on the plant, and amount of foliage are all important factors to consider. In temperate climates stem cuttings of young wood need to be taken in the spring from upper branches. As opposed to hardened wood, which needs to be taken in winter from the lower branches. The common practice on stem cutting lengths are between 5–15cm for soft wood and between 20–25cm for hard wood. Soft wood cuttings do best with approximately two thirds of the foliage removed, whilst hard wood cuttings need complete foliage removal.

Cuttings require a humid environment either by placing them in a propagator or plastic bag or in another confined space, where the air can be kept moist and partial shade is advisable to prevent the cutting/s from drying out. Cuttings in the medium are usually watered with a fine mist spray to avoid disturbing plants. The aim to keep the soil moist but not wet and the medium is allowed to almost dry out before misting again. A rooting hormone can be used to encourage growth and maturity in plants although it is not essential. Some cuttings will grow if simply placed in a jar of water, but the water needs to be changed on a weekly basis to prevent stagnation.

Graftingis a horticultural technique where tissues from one plant are inserted into those of another so that the two sets of vascular tissues may join together. This vascular joining is called inosculation. In most cases, one plant is selected for its good roots called the stock or root stock, the other plant is selected for its stem, leaves, flowers and fruits and is called the scion. The scion contains the desired genes to be duplicated in future production by the stock/scion plant.

In Japan this technique is most common especially with pines, such as the black, red and white species. The black pine found at low altitude is selected as the stock because of its potential for strong growth, the red pine from higher altitudes can also be used as stock material, but lacks the vigour of the black pine. At more higher altitudes the white pines are found, these have fine delicate foliage and are used as the scion and often grafted onto black pine root stock.

For successful grafting to take place, the vascular cambium tissues of the stock and scion plants must be placed in contact with each other. And both tissues must be kept alive until the graft has ‘taken’, usually a period of a few weeks. As there are many different types of grafting and much literature and audio visual presentations (Youtube) available, only one will be discussed here.

T. graft or cleft – is a common method used in bonsai where an insertion with a sharp knife is made into the stock. A vertical cut is first made followed by a horizontal at the top of the vertical cut allowing the bark to be peeled back revealing the cambium layer. The scion has it’s bark carefully removed showing the cambium still attached to the scion, which is then inserted into the stock making sure that the cambiums of both stock and scion are married together. Tape and or raffia is the wound around the join to ensure good bondage and to protect it from disease. The following illustration show this particular method.

T graft

In the next episode (Selecting material for bonsai part II) we consider Air-layering and collecting from the wild. Until then, BW, N.

Article 10 – ‘Selecting the correct pot or container’

Before we commence with the discussion on pots or containers, perhaps the following perspective might be of assistance in the interests of saving money.

Potential bonsai specimens purchased from a store, garden centre, nursery or indeed other sources will need training to suit a particular design. Sometimes, they are accompanied by a mundane ceramic pot, which is mass produced. Buying a more expensive pot purely for cosmetic values is a needles expense, because the design of your tree may change over time and probably will not suit or fit into that particular pot. Therefore, one buys another pot Ad infinitum resulting in a stack of pots that are redundant.

A potential bonsai regardless of its origin needs space to grow, to develop its root system, trunk girth, branches and ramification and it cannot do this if restricted in a pot. The solution is to make boxes out of chemically free scrap wood and old pallets usually free from a builders or timber merchant are ideal for this purpose.

The box can be made in any size to suit your needs for example, 30cm x 30cm x 25cm deep, but it will require plenty of drainage holes that are covered with plastic mesh to stop the soil from escaping. Such mesh can be the sort used to protect small trees from animals and can be found in most stores and garden centres and is inexpensive. Furthermore, this mesh is also ideal for covering the drainage holes of bonsai pots.

Wooden box

Pine in a box

The benefit of a box is that it gives plenty of room for ‘root-run’ establishing a strong and healthy root system needed for good Nebari. In addition, guy wires can be placed anywhere for stability and to aid in the tree’s design, which cannot be done if in a ceramic pot. Moreover, if undisturbed for example three years this will allow the tree to develop more quickly. In reality, a bonsai does not need a pot until it is at least 80% near to its final design and there is an important reason for this consensus.

A bonsai is a ‘living’ work of art and can be likened to a picture just like the work of Rubens, Goya and Rembrandt. These masterpieces are incorporated into heavy gilt frames to emphasize their meaning and message. Now imagine if we substituted the gilt frame for a plain satin finished aluminum one, the whole design frame and painting would be out of context losing its magnetism. Bonsai has exactly the same principle, the tree is the picture and the pot is the frame and both have to compliment each other in order to accentuate the overall composition.

But knowing which pot to select is not as easy as it may seem, because a tree in the wrong pot can actually lessen the visual impact diminishing the tree’s full potential. Alternatively, a tree in the right pot will look quite remarkable. Then how do we find the right pot?

Bonsai pots can be relatively cheap to buy as in for example those made in China and Korea, whereas Japanese and hand made pots tend to be more expensive. For example the small cream Japanese glazed oval used in the Tanuki experiment (See bonsai styles part I) was bought in 1975 for about the equivalent of about 20€ and if purchased today, would cost 6 times as much. In addition, there exist a large variety of shapes, sizes, glazed and un-glazed pots available. Therefore, when choosing a pot it is wise to examine the tree’s design, colour of leaves and bark and whether the tree is a conifer or a deciduous including those that fruit and or flower.

Generally speaking, the accepted rule is that un-glazed pots are for conifers, whilst glazed pots are for deciduous, but as you are the artist/designer the final decision is down to your own personal tastes. Nevertheless, to arrive at a suitable conclusion when selecting a pot, there are some points that may assist for example. The tree itself, pot shape, dimension, colour and texture.

In the articles ‘bonsai styles’ there were a selection of illustrations depicting various styles and from these we are able to determine if a tree is masculine or feminine for example.

A tree that gives an impression of strength through its large trunk and mature weather beaten nature, strong canopy including any deadwood it may have can be considered as masculine and Pines are a good example of this.

Alternatively, a tree having a more delicate appearance via its trunk’s gentle taper and delicate foliage can be viewed as feminine, such examples of this are the weeping silver birch Betula pendula and Acer Acer palmatum.

But some trees are able to project both masculine and feminine appearances for example. The Rowan Sorbus aucuparia with its bright red/orange berries may have good movement in its trunk, but has fine ramification at its apex can be considered to have both male and female attributes. Therefore, when selecting a pot one must consider both these characteristics.

Pot shape and dimension – are also considered to have masculine or feminine attributes for example. Deep pots with strong angular features are considered masculine whilst feminine pots are shallower with softer lines. The following images illustrate this meaning, 1. a deep rectangle pot with strong robust corners giving the impression of strength is especially suited to Pines, whereas 2. has delicate rounded lines suitable for flowering/fruiting trees such as Cherry or Quince. Alternatively, trees having wide canopies that may be considered neither masculine or feminine for example a Beech, are best suited to a wider shallower pots 3.


Other factors considered appropriate are the dimensions of a pot in relation to its tree for example. The depth of the pot should equal the diameter of the trunk just above soil level. For rectangular and oval pots, the size should be approximately the height of the tree. For round pots it should be about the tree’s height.

The colour and texture – of a pot can be used to enhance a tree’s particular feature for example, an un-glazed brown pot can highlight the ‘craggy’ brown bark of a Pine. Pinus sylvestris, a dark blue glazed pot could be used to emphasise the red berries on a Cotoneaster Cotoneaster frigidus a green glazed pot would enhance the leaves on a Beech. Fagus sylvatica. From these examples we see how a pot’s colour can be used to depict a tree’s particular feature.

Pot texture – For masculine pots textured finishes are ideal as they enhance the wildness of a tree’s rugged appearance however, some contend that a smooth textured unglazed brown pot is able to enhance the tree’s ruggedness even further. Pots with smooth finishes are more suited to feminine trees because their glazing highlights the tree’s feminine attributes. For trees that are considered neither masculine nor feminine should be in pots that enhance their best characteristics either glazed or un-glazed.

Referring back to the comments made earlier regarding the paintings of old masters (Rubens, Goya and Rembrandt) and of how both frame and picture compliment each other and that a bonsai in its pot is viewed in the same way; well this is what we try to achieve when combining a tree with a pot. But having said this, as you are the artist it is your decision when selecting a pot for your tree – what you believe to be ascetically right.

Nonetheless, one factor that is crucial when planting a tree in a pot is its position, meaning how it will look. In most cases all bonsai apart from semi-cascades and cascades styles are seldom positioned in the centre of the pot. They are positioned slightly to one side in order to achieve visual perspective and correct alignment. The illustration given below explains the importance of this.

In the next post we discuss the topic of selecting material for bonsai. So until next time. BW, N.


wrong position