Growing Bonsai from Seed

There are many ways of creating bonsai. You can use ordinary trees and shrubs purchased from garden centres and nurseries or you can use plants taken from your own garden. Alternatively you can start from scratch by taking cuttings and raising seedlings. There are advantages and drawbacks to each of the different approaches, but perhaps the most challenging is raising bonsai from seed. Growing bonsai from seed is a relatively slow process, but it can also be the most satisfying.. One of the main advantages of growing from seed is that you have complete control right from the very start.

Although raising bonsai from seed is a relatively slow process it is not as slow as one might imagine. Some very nice trees can be produced in as little as three or four years. It depends very much on how the trees are developed and trained. If seedlings are grown intensively they can attain quite thick trunks in a fairly short space of time. On the other hand if they are grown in small containers and never potted on, they will always remain very tiny. Creating a bonsai is in some respects like programming a computer. You can make it do almost anything you want it to.

Good quality seed is of course the key to success. If seeds are not viable to begin with, then no matter what you do, they will not germinate. The seeds should be purchased from a reputable dealer who can ensure that they have been stored properly or are relatively fresh.

Some seeds are easier to germinate than others. The easier varieties are usually those which do not require any pre-sowing treatment. Most hard-coated seeds from the temperate regions require this treatment in order to break the dormancy of the seed. Dormancy is nature’s way of ensuring that a seed will germinate only in the spring when there is no longer any danger of frosts. If a seed were to germinate in the middle of winter, the frost would soon kill off the young plant. In nature the winter frosts help to rouse a seed from its sleep so that when spring comes it will germinate freely and grow on to become a strong young tree. Under controlled conditions the cold and frost can be reproduced by placing the seeds in a refrigerator or freezer. Either is suitable.

Seeds normally come sealed in paper packets or plastic bags. In order to stratify them, put them in a plastic bag with a small quantity of water. The seeds should be allowed to soak in this water overnight before being put into the freezer. Most seeds will benefit from being put into the freezer for about four weeks. After this period they can be taken out of the freezer and sown in the normal way in a mixture of peat and sand or ordinary seed sowing compost. You can either leave the seed tray on a kitchen window sill or put it in an airing cupboard for just three or four days to start the germination process. The seed tray should be covered with a plastic bag in order to conserve moisture.

Once the seeds show signs of growth, the bag should be opened gradually so as to introduce air into the environment. If the cover is not removed then seeds tend to get long and lanky and there is also danger of the seedlings ‘damping off’ from virus infection.

Some varieties of seed take much longer to germinate than others. Hornbeam, hawthorn and sometimes Japanese maple can take more than a season to germinate. If seeds do not emerge after two or three months, it is worth freezing the entire contents of the seed pan in a plastic bag for another three to four weeks. Repeat the germination process again in the hope that they might sprout. If this does not work, leave the seeds in the garden so that they can be stratified during the coming winter. There is always a chance that they will germinate the following spring.

When the seeds begin to sprout, remove the seed tray from the plastic bag and keep the compost moderately moist but not too wet. Never let the compost dry out completely. Over-watering and under-watering are equally damaging.

When the seedlings have put out two or three pairs of leaves this is the best time to pot them on into individual pots. Potting is best done in the early spring and may be continued up to midsummer. If you have a greenhouse then you can continue to pot up right into late summer but no later than this. Seedlings are best potted up into individual two-to three-inch (5-7.5 cm) plastic pots to grow on strongly.

No shaping or trimming should be done during the first year. The seedlings should simply be grown on until they have sufficient vigour to withstand the training at a later stage. When the seedlings are well established in their individual pots (within two or three weeks they should be fed with a weak fertilizer to induce stronger growth.

In the second year the young seedlings can be shaped into bonsai. The roots should not be pruned at this stage as this will weaken the tree. You should decide fairly early on whether you wish to have a large bonsai or a smaller one. For a large bonsai, the seedlings should be progressively potted on into larger containers so that the tree will develop a fairly thick trunk. If you decide to keep a bonsai no more than three to four inches (7.5-10 cm high, the tree can be shaped into a tree of this size when it reaches a height of six to eight inches ( 15-20 cm) The extra height is to allow for pruning off the excess.

There are two basic ways of developing bonsai from seedlings. The first is the age-old Chinese method known as the clip and grow’ method. This involves constant clipping and cutting back of the shoots until the desired shape is achieved. The second method is a more recent one using copper or aluminium wire for bending the tree into the appropriate shape. In the clip and grow method two or three-year-old seedlings are allowed to grow strongly so that a moderate sized trunk is available. A seedling can grow up to 12 inches (30 cm) high in a flower pot if grown well. Seeds grown in open seed beds can sometimes attain a height of two to three feet (60-90 cm) in the first couple of years. Japanese maples and zelkovas can grow three to four feet (90-120 cm) in the same period. However since the objective is not to grow trees which are too tall, they should be cut back at regular intervals so that all the goodness is channelled into the trunk. In the clip and grow method, branches which are growing in the wrong direction are removed so that the leading shoot can be encouraged to grow in the desired direction. In this way the tree can be made to grow in any direction or shape.

Pruning is usually done in the spring and summer but not later than the late summer. In spring, shoots which have developed in the previous year are cut back to half their original length or to one or two nodes of the previous season’s growth.

The modern method of making bonsai is by wiring and is much simpler and quicker than the ancient clip and grow practice. A seedling of about two years old can be wired, but anything younger is not really suitable as it will not have developed sufficient trunk thickness to withstand the bending with wire.

The most basic shape used in bonsai is what is known as the informal upright or ‘S’ shape. In order to bend the trunk, wind a piece of wire of the appropriate thickness from the base of the trunk all the way up to the apex. This can be done with either aluminium or copper wire. The wire should be wound on fairly tightly: if it is too loose it will not have much effect. Once the tree is wired it can be bent into the desired shape. The wire should be left on for a complete growing season during which time it will set in the form in which it is trained. If the wire appears to be biting into the bark or trunk it should be removed and wired in a slightly different position so as to avoid disfiguring the bark.

21. March 2012 by admin
Categories: Bonsai, Featured, Plants | Tags: , , , | Comments Off on Growing Bonsai from Seed

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