TIPS TO KEEP YOUR BONSAI
HEALTHY AND HAPPY

Choosing a Bonsai | Feeding/Fertilisation | Soil |Repotting & Root Pruning | Watering | Temperature/Humidity | Planting from seed | Pruning | Wiring | Wind | Light | Rotating your tree | Dormancy | Displaying Bonsai | Pot Selection | Moss | Diseases | Pests | What to do with a sick tree | Overfed Trees

Below are some of the tips that I have gathered during my research before starting on this journey of Bonsai. Follow the links above to the different sections found on this page, or just browse at your will. I hope they also help you in your voyage.

CHOOSING A BONSAI

  1. Avoid trees with abnormalities such as spots or bugs on the leaves.
  2. Avoid "glued-rock" Bonsai - these are Bonsai that have rocks on top of the soil that are glued together and glued to the soil. This is done for shipping purposes so that the Bonsai stay in place and are not damaged. The problem with this technique is that it is hard for the water to permeate the soil and the glue seeps through the soil then dries and destroys the roots, resulting in the tree only living for about a year or so.

FEEDING/FERTILISATION

  1. There is absolutely no need to feed or fertilise a newly planted tree/seedling; in fact it is dangerous. The soil mix is all you need at the moment. Wait until the next feeding season arrives.
  2. Special Bonsai fertilizers should always be used at the recommended dose, but houseplant and garden fertilizers are best used at half strength, but twice as often.
  3. Care should be taken with fertilizers; always water well beforehand.
  4. If the fertilizer is too strong when applied, it will kill the delicate hair roots and damage root cells, making the tree impervious to watering.
  5. Your fertiliser should contain both macro and micro nutrients.
    Macro Nutrients:
    Nitrogen: Is absorbed more than any other nutrient. Produces rapid growth and gives the leaves and stems a healthy, deep green colour. Used in the synthesis of enzymes.
    Phosphorus: Needed for the formulation of seeds, flowers and fruit. Helps the plant to store energy for the coming winter and to harden off the roots and buds. Encourages plant cell division and encourages root growth. Also assists in making potassium available to the plant.
    Potassium: Helps plants to increase disease resistance. Improves stem and trunk rigidity. Helps the plant to overcome poor weather or soil conditions. Makes plants more vigourous. Essential in the synthesis of proteins and encourages the efficient use of carbon dioxide.
    Micro Nutrients:
    Boron, Chlorine, Carbon, Hydrogen, Oxygen, Calcium, Copper, Iron, Manganese, Magnesium, Molybdenum, Suplhur and Zinc.
    All are essential to plant health, but are only needed in small amounts.
  6. There are various meals that can be used such as:
    Bone Meal: This decomposes slowly and releases phosphorus. Naturally alkaline and helps to neutralise the acidity of peat-based or acidic soils.
    Cottonsead Meal: Is slightly acidic and is good for use with Azaleas, Camellias and Rhododendrons.
    Blood Meal: This is a very rich source of nitrogen, and also contains several trace elements. Be careful not to overuse this product as it can burn your plants.
    Fish Meal: It is high in nitrogen and contains several trace elements. Apply in late spring to boost plant growth, but it can burn your plants, so be careful.
  7. Inorganic fertilisers (chemicals) come in different forms: dry, liquid, slow-release, pellets, plant stakes, soluble solutions, and many others.
  8. Do not overfeed your Bonsai and forget fancy diets. Your Bonsai does not eat, it drinks!

SOIL

  1. Good compost or old manure should be worked into the top surface of the soil of your potted trees regularly.
  2. Soils consisting of very coarse grains will drain rapidly and retain very little water.
  3. Soils consisting of finer grains will still drain well and not become easily saturated, but will retain sufficient moisture for the tree.
  4. Flat dwellers will need a highly water-retentive mixture.
  5. Do not pat the soil down after watering. Patting the soil when wet causes compaction of the top layer, which dries to a hard skin, making it almost resistant to water penetration.
  6. Soil must provide stability for the plant, hold water and nutrients for the roots, and be sufficiently open to allow free passage of roots, water and air, as well as being free draining. Water must flow through the container easily and not stand on the surface for a long period of time.
  7. Surface soil should be kept friable and loose.
  8. The soil should essentially be pH neutral (between 6.5 and 7.5).
  9. A good Bonsai soil mixture should be composed of about 75% inert aggregate and 25% organic materials.
  10. All components in Bonsai soil must be screened to remove all large chunks of material.

REPOTTING & ROOT PRUNING

  1. Repotting and root pruning must be carried out in a cool, shady place.
  2. The roots must not be exposed for too long.
  3. In climates where the air is dry and hot with minimum humidity, root pruning should be light.
  4. In sub-tropical climates where humidity is higher, root pruning can be more severe.
  5. Deciduous trees can only be transplanted when dormant, usually in June or July (in Southern Hemisphere), while all evergreens and conifers can be moved very easily at any time of the year.
  6. When a tree is dormant, root pruning can be much more severe.
  7. The tree is carefully removed from the original container and the soil removed gradually by loosening it with your fingers. Usually the centre has few roots and by digging in with your fingers, the root mass can be dramatically reduced.
  8. Never ever shake the soil off the roots.
  9. Try to ensure that as much of the old soil is removed as possible when transplanting. Incompatible soil mixtures can cause problems in maintaining adequate moisture levels and fool you into thinking that the soil is completely saturated when it is not.
  10. Before the tree and soil are put back into the pot, it is very important to cover the drainage hole/s with rectangular pieces of mesh so that the soil is not washed out. Cut a line of wire and form a loop with a tail at each end. Push the tails of the wire through the holes until the mesh is flat against the bottom of the inside of the pot, then flatten the tails to the bottom of the outside of the pot.
  11. The root mass is then placed in the container, clipping off only the roots that are in the way.
  12. Once the tree is in position in the container, soil mix is added until the container is full. The soil is worked into the root mass by gently probing in a circular motion with a chopstick or thin dowel.
  13. After this, the soil can be firmed down with your fingers until the texture feels right and the tree stands firm.
  14. A good test for the correct moisture content of your soil when transplanting is to ball a handful of soil by squeezing fairly hard, then open your hand and tap the ball of soil; if it crumbles, it is just right. If you cannot ball it, it is too dry, and if it does not crumble, it is too wet.
  15. Dead roots in a pot will decay, and due to their length being comparatively shorter than trees in the ground, this decay can reach right up to the trunk and the whole tree could die as a result.
  16. Tropical and Sub-tropical trees should be repotted mid-spring as the growth tends to slow down in winter and speeds up again in spring as the days grow longer.
  17. When a tree is removed and there are no roots, it may mean that the tree was pot-bound and the roots have started to decay.
  18. When pruning the roots, cut them back until the root ball fits the pot with a clear margin of ±25mm all round.
  19. After repotting, keep the tree where it will be protected from frost, direct sun and wind until new growth has started.
  20. Do not feed repotted trees until new growth is well under way.
  21. Wedge repotting - remove small wedges of the soil from around the tree without removing the tree from the pot. Fill these holes with fresh soil, rich in nutrients and clean up the landscape so that the refills are not so obvious.

WATERING

  1. NEVER water to a routine. Watering to a routine commonly leads to permanently wet compost, leading to problems associated with over watering.
  2. Water once to wet the surface, twice to penetrate the soil and thrice to make sure the water has permeated the soil, especially the base of the tree.
    First watering: water until the water reaches the brim of the pot, wait a minute or so to allow the water to soak into the soil.
    Second watering: repeat the process and this time you should see some water coming out of the drainage holes. If not, repeat.
    Third watering: wait for 15-20 minutes and repeat the process. Again you should see water coming out of the drainage holes. Watering in this way ensures that your tree and soil is receiving and holding enough water, while at the same time, without the risk of over-watering.
  3. Method to determine when to water: insert a skewer or toothpick (depending on the size of your tree/pot) into the soil, halfway between the tree and the pot. Pull the stick out on a regular basis and check if the tip is damp. (If it is, then you should not need to water. If not, then it is time to water.) This is a useful method, as often the top surface of the soil tends to dry out due to wind or sun, before the rest of the soil has.
  4. Wash Bonsai down with a spray, especially wetting the underside of the leaves. This keeps the foliage in good condition and discourages red spider mite as they drown in the tiny droplets of water. Wetting the leaves lowers the immediate temperature and refreshes and cools down the leaves, thus lowering transpiration (in much the same way that humans perspire).
  5. It is very good horticultural practice to arrange to do your last watering around 2 or 3 o' clock in the afternoon.
  6. Holiday watering system: fill a 5 litre plastic bucket with water. Insert the business end of a drip administration set through the bottom. Place the bucket higher than your tree and the regulator will control the water.

TEMPERATURE/HUMIDITY

  1. Always try to maintain even temperatures and make sure any changes in temperature are gradual.
  2. For balcony grown trees: make a humidity tray by filling a plastic tray to the rim with pebbles, and filling it with water. The tree and container is then placed on top of the pebbles, ensuring that the drainage holes are not below the water level or blocked by the pebbles. This creates a microclimate with a little humidity around the tree, making for a happier and healthier Bonsai.
  3. When using a humidity tray, the flatter the better as this keep the algae and pests under control because the whole amount of water should evaporate each day.

PLANTING FROM SEED

  1. Seeds with a fleshy coating must be dried and cleaned thoroughly before planting.
  2. Very hard-skinned seeds should be soaked by pouring hot water over them and left to soak for 12 hours.
  3. Stratify all seeds by keeping them in the refrigerator for up to a week before planting. This helps to activate the seed and good germination will result.
  4. The young saplings should not be transplanted until they are well established. Then they should only be moved when dormant, during July and August (Southern Hemisphere).
  5. When the seedling is 5-10cm high, and has numerous leaves, nip the top growth to encourage branching. This is the first step to shaping your bonsai.

PRUNING

  1. As branches develop, nip off the growing tip when the branches are long enough, remember to keep the lower ones longer than the upper ones, and to space them evenly around the trunk by removing unbalanced growth.
  2. Divide the tree into 3 equal horizontal sections.
    The bottom third should be cleared of all branches.
    The middle third should have 3 strong branches, the lowest to the left or right, but over the container, the second opposite the lowest branch, but a little higher, and the third still higher, but to the back.
    The top third will have 5 to 7 branches, with 1 or 2 pointing slightly forward. In this way, branches will be kept to a minimum.
  3. Train the branches in a slightly downward direction, never upwards.
  4. A fundamental law that must be kept in mind and practiced at all times: the earlier and harder the pinching back, the slower and smaller will the resulting new growth be.
  5. Shoots on the trunk and at the base of the branches - adventitious shoots - should be rubbed off, except if they are needed.
  6. All cuts should be made right against the leaf stalks or buds. Stumps can cause dieback.
  7. Allow shoots to develop 6 or 8 leaves before trimming them. This gives the tree a chance to grow healthily and vigorously.
  8. Do not cut conifer needles, pluck them by hand.
  9. Flowering and fruit bearing trees should be pruned after they have flowered, especially in the case of tip bearers.
  10. Always cut at an angle - oval cut - it looks better and heals quickly.
  11. Always try to have all oval cuts facing inwards and/or backwards. This makes them less conspicuous and does not distract from the overall look of the tree.
  12. Broadleaved trees with opposite foliage: Once the new shoot has 1 pair of leaves, you can pinch out the minute pair of emerging leaves in the centre with a pair of tweezers. This will arrest the growth of that shoot and will prevent the remaining leaves from growing too large. Longer shoots can be snipped back to just above a pair of leaves. Two new shoots will grow from where the leaves join the cut shoot. Cutting a longer shoot at its base will induce many new, smaller ones to emerge from around the wound.
  13. Broadleaved trees with alternate foliage: Once the shoot has 2 full sized leaves, snip off the growing tip to stop it growing longer. A new shoot will soon emerge from the base of each leaf. To build a dense mass of twigs, let each shoot grow until it has 5 or 6 leaves and prune it back to 1 leaf. Not only will a new shoot grow from the base of the leaf, but also many new buds will form around the base of the shoot. Trees with very small leaves can be trimmed almost like a hedge, but cut each shoot individually, between the leaves, not through them.
  14. Spring-flowering trees: As soon as flowering has finished, prune out any of last year's shoots which spoil the neat outline of the tree. Any older spurs can also be thinned out at this time. Let new shoots grow unhindered until late summer. Prune back to allow 2 or 3 new buds to remain.
  15. Pines: As the needles begin to peel away, pinch off the top one- to two-thirds of the shoot. New buds will form at the broken point for next year. Pull off most of last year's needles to keep the tree neat. Allowing the candle to develop fully and removing it all in late summer will encourage new buds to form further back down the branch.
  16. Junipers: Tufts of dense foliage can be gripped between the thumb and forefinger of one hand while the tips are simply pulled off. Extension shoots should be cut back almost to the base. Cutting back the central spine of all branchlets will encourage tufts of new foliage to burst from branch intersections.
  17. Other Conifers: Allow the shoots to grow until the leaves begin to darken and snip the shoots back to keep the tree neat. If no buds develop on the remaining part of the shoot, it can be completely removed the following spring. The buds that form in its base will grow to replace it. Leave very short shoots unpruned.
  18. Pines and Other Conifers: Allow shoots to grow unhindered on branches you want to shorten and in late summer, remove them completely. Make sure that you leave some foliage on last year's growth. During the winter, and into the following summer, new buds will form back along the branch. Once these buds have begun to harden, you can prune back to them and use them to rebuild the foliage mass.
  19. All Broadleaved trees: Pruning back close to dormant buds at old leaf scars or internodes, or points where branches fork, in midsummer induces these buds to develop. Leave a short stub at first and remove it when the new shoots have hardened.
  20. Wound sealant should be used for after branches have been cut. The easiest way to apply it is to use something small but round and that has a medium sized diameter depending on the size of your tree.
  21. Make sure you use a sealant that you have to apply manually because if you use a spray sealant you will more than likely end up spraying too much of your tree and it often comes out so fast that you end up with it dripping/running all over the place.

WIRING

  1. It is pointless, and dangerous, to wire an unhealthy tree. The way that wiring works is that, in bending the wood, you stress, and sometimes damage the cells. The tree, while repairing the damage, grows into the shape imposed on it by the wire. So if you wire a tree that is not in full vigour, it is unable to complete the repair, perhaps losing the branch, or dying in the process.
  2. Wiring can be done at any time of the year, however if applied in mid to late summer, when the tree is in active growth, it will set into shape much quicker.
  3. It is not advisable to try to alter the angle where the branch meets the trunk, this will most certainly cause the branch to break off. If you need to lower the branch, start at a point further out.
  4. Copper wire must be annealed first by passing it through a flame to almost red-hot before it can be used. This dulls the wire, making it less conspicuous, as well as easier to handle.
  5. When annealing, the wire must be heated ONLY until it glows red and then immediately removed from the heat and allowed to cool slowly. If the wire is overheated, it will crystalise and crumble the first time you try to use it.
  6. Try not to over-wire your tree.
  7. Judge the gauge of the wire before using it. It should be strong enough to bend and hold the branch in position.
  8. The length of the wire should be one-third longer than the length of the area that you are planning to wire.
  9. The coils should be fairly evenly spaced out - ±10mm apart.
  10. The coils must not be too tight as wire damage could occur as the branches/trunk thicken.
  11. When wiring your branches, do not arch them, but keep them fairly straight below the horizontal.
  12. Always follow the original curve of the trunk/branch first, and then move away from this curve if necessary.
  13. When wiring the trunk start by pushing the wire into the soil at an angle.
  14. Always coil in the same direction throughout (clockwise or anti-clockwise). It makes it easier to remove afterwards.
  15. When wiring a branch, first put a few coils around the trunk below the branch and then move onto the branch, starting from below the branch.
  16. For two branches close together, make a hairpin around the trunk, coil once or twice, and then use each end to wire a branch.
  17. The wire is to be left on for at least 9 months for all conifers, and for 3 or 4 months for all deciduous and evergreen trees.
  18. When bending the branches, always keep your thumbs together to maintain even pressure and to reduce the chance of breakages.
  19. Check once a week for signs of the wire cutting into the bark. As soon as you see this beginning to happen, remove the wire immediately.
  20. If you need to reapply the wire, do so in the opposite direction to the first application. This is kinder to the bark and less likely to interrupt the flow of sap.
  21. For older trees and thicker branches/trunks, rather use stretching instead of wiring.

WIND

  1. Poor air circulation around the foliage can encourage fungal diseases such as mildew, or attacks by some pests like red spider mites.
  2. Trees should be sheltered from strong breezes at all times.
  3. Protect hardy trees from the drying wind in winter.
  4. For trees left indoors, air circulation can be controlled simply by leaving the window open. In winter, or on wet days, this can be done by using a fan on the lowest setting to gently waft your tree.

LIGHT

  1. Unless you are going to provide artificial light, your Bonsai needs to be placed as close to a window as possible, so that it receives at least 2 hours of direct sun everyday.
  2. If you are not getting enough sun, use an overhead lamp with a full spectrum flourescent buld, like those used for reptiles. Keep the lamp about 8-12 cm above your Bonsai, because if kept closer the bulb could burn your tree. This is also important if you mist your tree regularly as the light through the droplects could burn the leaves of your tree. Keep the light on for 12-14 hours a day to simulate normal sunlight hours.
  3. Never place your Bonsai on an inner window sill with the Bonsai trapped between the window and drawn curtains as the temperature at night could be much lower in this area.

ROTATE YOUR TREE

  1. To maintain good depth to your foliage, you need to rotate your tree regularly making sure that the front and back of the tree receive adequate light (this does not need to be done if you use an overhead light).

DORMANCY

  1. Some trees require a period of dormancy as it is an essential part of their life cycles.
  2. While dormant, you should check your tree for water once a week.
  3. Generally you should only need to water once a month, but make sure that the soil does not become overly dry otherwise they will be very difficult to revive come spring.
  4. Also, make sure that they do not become too wet during times of low temperatures otherwise your tree will become very susceptible to fungal infections.

DISPLAYING BONSAI

  1. Trees should be kept on slatted benches, raised to at least table height.
  2. Plant the tree off-centre, a little to the back and a little to the side of the container.
  3. Your tree should not be more than one-an-a-half times taller than the length of its container. If the tree is too tall, make a new apex.
  4. It is part of the philosophy of Bonsai to expose some strong surface roots, which symbolize strength and stability.
  5. Ideally the roots should lie so that their top half is above the ground with no space between the roots and the soil. These roots should radiate outwards to create a natural balanced look.
  6. The trunk should have a good base with the roots radiating at soil level or slightly above.
  7. The trunk should have a good taper; ideally broad at the base and thin at the top.
  8. Great age of the tree can be suggested with any of the following aspects: dramatic surface roots, dramatic trunk taper, downward sloping branches, deadwood, and trunk and branch movement.
  9. A good Bonsai has a triangular shape, with a front designed for primary viewing, but looks good from all angles.
  10. Remember this: "Ichi-miki, Ni-eda, San-nebari" - First the trunk, secondly the branches, and thirdly the roots.

POT SELECTION

  1. Don't think that the tree is the only thing that the viewer will see when they look at your creation. Your Bonsai is not just a tree, but all the aspects that make up the whole display, including your pot.
  2. Base your pot selection not on the price tag, but on the suitablity of the pot to be in harmony with the tree.
  3. Trees with massive trunks will look better in heavy containers.
  4. Trees with lighter elements belong in lighter, more delicate pots.
  5. A cascade tree belongs in a proper cascade pot, and not in a shallow tray.
  6. Forest planting look better if they are planted in low wide trays.
  7. A Bonsai should be planted in a pot that is deep enough to comfortably sustain its health and life.
  8. An unglazed container is always correct for any tree, and almost mandatory for evergreens.
  9. Glazed containers are usually best for deciduous trees, or trees which bear flowers or fruit.
  10. Trees that exhibit "masculine" design elements should be planted in more angular containers.
  11. Trees that exhibit "feminine" design elements should be planted in containers with softer flowing lines.
  12. The width of the pot should be a little more than two-thirds of the total tree height.
  13. For trees that are wider than they are tall should be planted in pots that are slightly less than two-thirds the width of the tree.
  14. The depth of the pot should be about the same as the width of the trunk base at its widest point.
  15. The width of the container should be slightly narrower than the spread of the longest branch in the front and back.
  16. The container selected should always be subordinate to the tree planted in it - remember, the TREE IS THE POINT.

MOSS

  1. Moss can be propagated by collecting as much as possible by scraping it with a knife and allowing it to dry out properly. Once completely dry, rub it into a fine dust and store in an airtight jar. It will last for a long time.
  2. Apply the moss by watering the soil, and then dusting it evenly over the soil. Place a few squares of cotton gauze over the area to keep the spores in place. Water the soil gently until growth starts.
  3. Moss should not cover more than 50% of the soil surface. It absorbs the essential water that the tree needs.

DISEASES

  1. Fungal and other diseases are difficult to diagnose and treat. Consult either your local library, related websites or ask for advice from your local Bonsai Kai.
  2. Root Rot: shift to better draining soil, water less often, give your tree more sun (if appropriate), decrease the humidity, stop misting, give it more light and air circulation.

PESTS

  1. Watch very closely for Red Spider Mites: these are practically microscopic and can be seen with a 5x or 10x strength magnifying glass. They live on the underside of the leaves. Look for webs, debris or the translucent round eggs.
  2. Two Spotted Mites: these are smaller and translucent except for two small dark spots on their backs and can be seen with a 5x lens.
  3. Mites, aphids, mealy bugs, scale and all potential pests can be taken care of if caught early and sprayed with an insecticide. I recommend the Wonder Garden Gun.
  4. Always remember that some systematic insecticides can prevent infestations of some insects, but you are living in the continual presence of a deadly chemical.

WHAT TO DO WITH A SICK TREE

  1. Ensure that your tree is well watered. The soil must always be at least moist.
  2. Feed regularly and adequately.
  3. See to it that your tree gets enough light, this is particularly important for trees kept indoors.
  4. On repotting, water the tree with a fungicide.
  5. Repot your tree regularly with an open compost.
  6. Spray your trees regularly with both insecticides and fungicides.
  7. Treat all major cuts with a sealant.
  8. Use sharp tools to avoid making jagged cuts when pruning, they will allow infection into the tree.
  9. Do not keep unsuitable species indoors.
  10. Under no circumstances should any tree from an area of the world subject to hard winters, be kept indoors for more than a few days at a time.
  11. Always select species from subtropical areas if you wish to keep Bonsai indoors.

OVERFED TREES

  1. Place your trees in full sunlight all day.
  2. Allow your tree to die out.
  3. Repot the tree in an open compost at the first opportunity.

Last updated 2003.05.04