HOW TO GROW AND CULTIVATE BONSAI

The word bonsai simply means a plant in a container. This can be a tree or a shrub or even forms of grass. However, it would be reasonable to assume that it is more readily understood as a tree or shrub that has been trained in a miniature form grown in a pot. The art of cultivating bonsai trees and shrubs is considered a novelty in the West. However, they have been grown in China and Japan for 600 years. Although their origins are shrouded in time, it would appear that the Chinese were the first to start transplanting small trees, found in the wild, into ornamental pots. Why they started pruning and training these trees to look like replicas of their giant cousins is not known. It has been suggested that it was more or less an accident – a tree that is small and growing in poor soil will inevitably grow at an accelerated rate if transplanted into a nutritious compost. After a while. these plants would simply outgrow the size of the container and have to be cut back for easier handling. In time, it was realized that pruning certain branches achieved a more artistic effect and so the art of bonsai had begun. The original transplanted trees were probably Chinese – and bonsai is still practised there – but Japan has become better known as the country that developed the art and introduced the styles we know today.

STYLES

One of the original forms of tree resembled a pyramid, the trunk being absolutely straight and tapering towards the top. the branches forming the sides of the pyramid. This was followed by a style still used and called the formal upright. The trunk is straight and tapering with the branches evenly spaced around the tree – the whole giving rather a stylized effect. However, except with mainly evergreen trees, such as Pimis (pines) and Juniperus (junipers), this elaborate stylizing coupled with considerable bending and twisting of the trunks has now more or less given way to softer more natural forms.

It is difficult to give indications of the height of these plants, but as a guide some are still only 60cm (2ft) after 60 or so years.

There are still definite divisions of style when considering bonsai. The most popular form being the informal upright tree. Trees can also be trained to appear like a tree on windswept moorland, more or less parallel to the surface of the soil. and called the semi-cascade. The cascade tree is one growing so that the top half of the trunk actually appears to grow downwards, sometimes reaching 60-90cm (2-3ft) below the top of the tree. This style represents a tree growing on a mountainside or cliff face. Another style is a group of trees grown to look like a grove or small forest. With this form, perspective is very important. The largest tree is planted at or near the front of the group, with the smaller ones at the back. This gives a feeling of depth to the group. Croups can be any number, from two upwards. With the exception of two trees, these will always be planted in odd numbers, as it is difficult to achieve the right effect with even numbers.

POTS

The pots form the basis in which bonsai trees are grown. Except in a few instances. they must always have drainage holes to allow surplus water to escape and also to permit the circulation of essential oxygen around the roots. They should also be highly fired, so that they are resistant to frost damage. This is because for part of the year the plants should be stood outside in the garden or placed on a balcony. The pot should be considered in the same way as the frame to a picture, not detracting from the beauty of the tree. but rather enhancing it. for heavy-looking trees like pines, heavy, rectangular and formal pots are often used. For forest groups, wide and very shallow pots are the best.

DISPLAY

One of the most important things to remember about bonsai trees is that they should not be considered solely as houscplants. Even if the tree originated ‘ in Japan, it should be remembered that the Japanese climate is similar to our own. Practically all bonsai trees benefit from a sojourn outside on a balcony or in the garden.

As this is the case it is worth constructing a raised table (size will depend on the number of trees) on a balcony or in a sheltered part of the garden. For ease of care, plastic, windproof netting or wooden laths can be erected over and behind the trees. This will help to protect them from excessive wind and sun. This outdoor position should be regarded as their permanent home. Bonsai plants are not. by their very nature. houseplants, although they can be brought indoors for a short time – preferably not longer than four or five days. When they are indoors they should be given as much natural light as possible in a draught-free position that does not become too hot. After they have been admired inside they should be returned to the fresh air. when their place indoors may be taken by another tree. In the winter it is very important that they should not be transferred from a hot lounge to a frosty atmosphere outdoors in one step. They should be gradually acclimatized to the cold by putting them in a cold room for a day and then by protecting their roots in a box of straw or peat for two or three days, when they rejoin their companions.

STARTING WITH BONSAI

‘There are a number of nurseries that specialize in the importation and growing of bonsai trees, and with their increasing popularity small displays of trees can often be seen in garden centres and the larger departmental stores. Some of the trees for sale will be genuine Japanese bonsai specimens, others will be those grown in this country. When buying a tree, make sure that it is in good condition – looks healthy, not damaged. free from pests and diseases. Check that the pot has drainage holes and make sure that it is resistant to frost damage. If you would like to start a bonsai tree yourself, suitable subjects can often be found in garden centres. In this case. look for deciduous trees or shrubs with fairly small leaves.

Small trees growing in woods and moorlands can quite often be transplanted into a container. Before you attempt this, however, ensure that you have permission from the owners of the land. If you find a suitable subject and have

REPOTTING

Repotting a bonsai tree is sometimes considered a daunting task, but it need not be so. It is advisable to repot the trees in early spring before the leaves start appearing. Generally speaking, this is during March. If a tree is left too long without repotting it will become pot-bound. The roots grow, gradually filling the pot and the original compost is pushed out in tiny amounts until there is little left.

For young trees up to ten years old, repotting is necessary every one or two years. For older trees it can be anything from two to ten years. To decide whether to repot, first tap the edges of the pot gently so that the tree may be lifted out. If the root-ball appears to be a mass of roots then it is time to repot. First of all, tease the outer roots away from the root-

been given permission to remove it. this should be done in the early spring. mid-February to mid-March, when the tree is still dormant. If the tree is little more than a seedling, two or three years old. it should be possible to remove it directly from the ground with little disturbance to the roots, except in the case of trees with long tap roots such as oak. Shake off the surplus soil from around the roots, wrap them in wet moss or newspaper and put them in a plastic bag. At the same time, the top should also be pruned back to remove any crowded or spindly branches.

Make sure that your potential bonsai tree is kept moist during the journey home. If it has a lot of small fibrous roots near to the trunk, it can safely be planted directly into a container. If this is not the case, prune the roots back to within 15cm (6in) of the trunk and plant it in the garden for a year.

CARE AND CULTIVATION

Bonsai trees spend a major part of their life outdoors and it is essential for their general health that they are watered regularly. During the winter, the humidity and the increased rainfall will often be enough to keep a tree moist for weeks at a time during its dormant season.

During very hot spells in the summer. this will often be necessary at least once. and sometimes twice, a day. Never let a tree dry out. as only a few days without water can cause its death. It is preferable to use rainwater when available, but tap-water that has been allowed to stand overnight is perfectly adequate. Every ten days to two weeks during the growing season – late spring to mid autumn – a weak, liquid fertilizer should be added to the water. All plants need nutriment for their growth and health. It is a fallacy to believe that bonsai trees are starved to achieve their smallness. Regrettably, bonsai suffer from the same pests and diseases as other plants and trees, so watch for these too. Keeping the top growth of the tree pruned back is important to maintain and improve the look of the tree and to stop the top growth becoming too large for the roots to cope with. As most bonsai trees are hardy varieties, special winter protection is usually unnecessary even while the plants are standing outdoors. But hard and continuous frost can cause damage.

ball using a pointed stick or even a 15 cm (6in) nail, until approximately one-third of them around the outside and underneath the tree are hanging like a beard. Using a sharp and sterilized pair of secateurs or scissors, prune these back almost to the remaining root-ball, leaving a small fringe.

Wash out and dry the container and place small pieces of perforated mesh or crocks over the drainage holes. Follow this with a layer of sterilized grit and a thin layer of potting compost, pour this in around the sides of the root-ball and work it in with your lingers until you are sure there are no air pockets, and the tree is firm and stable. If the tree is at all top-heavy it will sometimes be necessary to wire it into the pot. through the drainage holes. using gardening wire.

Water thoroughly and place in a protected position until the new roots start growing. Trees planted over rocks, so that their roots are in the soil, should also be repotted in this manner. The compost for evergreen trees should be seven parts John Innes compost to three parts sterilized grit. For deciduous trees, eight parts John Innes compost to two parts sterilized grit. When repotting groups of trees, this can be done in two ways. The easiest method is to treat the group as a single tree and proceed as previously described. The alternative is to remove the group from its pot and cut out complete segments of soil, as if cutting a cake, then proceed as previously described. Trees planted directly into rocks cannot be repotted without breaking the rock and probably killing the tree. Fresh compost is added by considering the soil in which they are planted as a cake, and removing sections around the trunk of the tree. These are then filled with fresh compost.

TRAINING BONSAI TREES

Pruning a bonsai tree to maintain its health and make it look beautiful is necessary. During the winter and early spring, heavy branches that are dead or unnecessary should be removed as close to the main trunk as possible. When pruning back a branch, make sure that the cut is made above a secondary branch or growing point. To maintain its health and to create a lovely specimen, it will be necessary to shorten all growth to the first or second leaf or set of leaves. Over the years, this will give you a tree with a strong trunk, firm branches and the twiggy outline of a tree in the wild.

Pines only need pruning once a year. This is done during spring when the new shoots have elongated enough for the needles to start slicking out. Two-thirds of their growth should be removed. leaving only two shoots at each growing point. Further shoots should be removed completely.

Spruce trees should be pruned in the same manner, as their new growth appears, but care should be taken not to damage the new needles. Junipers, chaemacyparis and cupressus trees – which are evergreen trees with articulated needle-like leaves-should be pinched out with the fingers throughout the growing season to encourage full and bushy growth.

Trees that fruit and flower on the previous year’s growth should not be pruned after the middle of July, except for their tips. Other deciduous trees can also have their leaves removed at the

end of June, provided they are growing vigorously.

The main part of the leaf is cut off leaving the leaf stalk (petiole). This causes a false autumn and after a few weeks the petiole will shrivel and drop off. New leaves that are smaller and better coloured will then appear. If there is any doubt as to the health of a tree, do this on a small branch first to test how long it takes for the leaves to return. Most deciduous trees are suitable for this treatment, but not flowering or fruiting trees. Correct pruning and training are essential to the well-being of a bonsai tree. Branches can usually be trained in any direction required by pruning to a suitably positioned bud. However, there are occasions when branches have grown away from the desired line and wiring or tying into position is necessary.

Wiring consists of selecting a length of wire about one-third longer than the branch to be trained and whose pliability is slightly less than the branch. The wire is twisted gently around the branch at an angle of about 45 degrees after anchoring the end nearest the trunk over another branch or looping it around the trunk underneath itself. It should now be possible to bend the branch carefully into the required position.

This wiring and shaping should only be done during June or July when the branches are at their most pliable. For deciduous trees, the wire should only remain on for four or live months. For evergreen trees that are slower to take shape, a year is often required.

SUITABLE SUBJECTS FOR BONSAI

When considering a potential tree to be trained as a bonsai subject, it is always best to choose a type with small needles or leaves, unless the tree is to be grown specifically for the flowers or fruit, such as flowering cherries or peach (Primus) or a crab apple (Mains). The following list of plants is not comprehensive. and there are many others that can be used.

Evergreen subjects

Pines [Pinus) need repotting every three

or four years. They should have plenty of

sunshine and only moderate watering.

Allow only two shoots on each growing

point and prune to two-thirds their

length.

Junipers (Juniperus) should be repotted

every two years. Never allow the plants

to become dry. Always linger pick new

growth to give shape.

Japanese cedars [Cryptomeria) can be

treated as junipers.

Firs and spruces (Abies and Piceas) are repotted every two to three years. They need plenty of water and moderate sunshine. Prune the new growth as it appears by pinching and twisting out one half of the elongated buds.

Flowering subjects

Winter jasmine (Jasminimi nudiflorum) is very strong and can be repotted at any time. Allow it almost to dry out before soaking thoroughly. Prune to shape, as required.

Peaches and cherries (Primus) need repotting annually. Prune back two-thirds of each branch after flowering. The plant should not be excessively watered, but rather kept slightly dry.

Fruiting plants

Herringbone cotoneaster (Coloneaster IwrizonUilis) is repotted annually. Give ample sun and water. Although it is a well-known garden shrub, it is one of the easiest to train. It can withstand considerable wiring, but needs frequent pruning to keep it in shape. Crab apple (Mains) needs repotting yearly into good compost. It requires a lot of water and moderate sunshine. Prune back one-third after flowering and stop the terminals on new shoots throughout the summer. Firethorn (Pijracantha) is repotted annually. Do not allow the roots to become dry and set the plant in a sunny position for it to bear fruit. It is only necessary to prune the plant sufficiently to maintain an attractive outline and shape.

Deciduous subjects

Maples (Acer) are a large family of trees and shrubs, which need repotting yearly. Do not allow the roots to become dry and remember that harsh sunlight burns the leaves. Keep the plant in semi-shade. Prune young growth as it grows. Prune the main branches only in autumn, as they can bleed. Leaf cutting can be done in June. Beech [Pagus sylvatica) makes a handsome tree and should be repotted every second year. Given plenty of water and sunlight. Prune as necessary, remembering the form of these beautiful trees. Oak (Oucirus) is not often used as the leaves are normally too large. The tap root, which is very vigorous, should be cut back each year during repotting. Ensure that the roots remain moist, and avoid very hot sun. Prune back hard during the growing season. Watch for insect attack and spray when necessary. Elm (Uhnus) is repotted annually. Give sufficient water to keep the roots moist and place in a position with moderate sunshine.

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