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Bonsai Doctor


Welcome to the new Bonsai Doctor page!

This page has been created to help you quickly and effectively diagnose a potential issue with your Bonsai and take positive action to nurture your tree back to full health.

The following information aims to cover the most common problems you may encounter when growing Bonsai, and a number of possible solutions. This information does not cover all potential issues so if you cannot find the solution to your problem, please contact us with photos :


Have a read of the Basic Do’s & Don’ts check list below and make sure you are giving your tree a happy home:


Basic Do’s & Don’ts Checklist


Do allow plenty of light with good air circulation. Your tree needs sun light to photosynthesise and grow and will not survive without it. If the tree is indoors, make sure it is positioned in or close to a window*.

*If the window is South facing (getting the peak mid-day sun) protect the tree by diffusing the light, or move the tree further away from the glass. If the light is too intense for the tree the leaves will burn.

Do water regularly when the tree needs it. The Bonsai tree will not like being kept wet all the time, but will be very unhappy if it is allowed to dry-out to much. Check the surface soil of your tree everyday whilst you are getting used to how often the tree needs water;

If the soil feels moist: don’t water, just place your tree back in its well-lit position.

If the soil feels dry to the touch: stand the tree in water, just below the rim of the pot and allow the tree to soak up the water. Wait until fully saturated (15 minutes is usually long enough) then place back in its well-lit position.

– Don’t keep fully saturated all the time! Allow to dry a little and then water.

Don’t give your tree hard-water! Plants do not like hard water and it will eventually kill it. Collect rain water to give to your Bonsai or bottled water. Tap water is fine in soft water areas.

Do mist spray frequently. Check surface soil dryness before spraying; to check when the tree needs watering again as described above. Late afternoon/evening is the best time to spray due to strong sunlight on wet foliage can burn the leaves.

Do feed regularly when growing well. If tree appears unwell stop feeding until problem is resolved. You will know the tree is recovered when it starting putting out new growth. We recommend slow release fertiliser – dry granules rubbed in to the soil surface: in good compost, one small pinch per month during growing season. Continue to feed indoor trees in winter if growing vigorously; stop feeding when dormant or poorly.

– Don’t feed a tree if it looks unwell! Fertiliser is not medicine and will not make a tree better if it’s struggling. A Bonsai will only use the feed if its healthy and growing well.

Don’t position an indoor Bonsai near a heat source (radiator/TV/computer/fire). This will dry out the tree and kill it.

Do re-pot the tree every 1-2 years or the tree will get pot bound. When your Bonsai has used up all of the available nutrients in the soil, and its roots start to wind around the pot, it is time to re-pot and give your tree a new lease of life. Replacing the compost with a good, gritty, bonsai compost regularly (every year or 2) will give your Bonsai tree a healthy life. Root prune only the roots that hang down below the fibrous root ball.

*Root pruning allows your tree to live in the same pot for many years (not potting up in to a larger pot), must only be done at the right time of year – typically this is early spring.

Don’t root prune a tree at the wrong time of year! Only early spring can you do this without upsetting your tree too much and only prune the roots that hang down below the fibrous root bbball.

Do visit the FAQ page on our website: , for further information on Watering, Mist Spraying, Feeding, Situation, Repotting / Root-pruning, Compost & Common Problems.

Our Booklet ‘Introduction & general care of Bonsai’ is uploaded on to our ‘Bonsai Guide’ page on our website.


Have a read through some of the various symptoms that your Bonsai may be exhibiting and the possible solutions.



Bonsai Symptoms



Some leaves are turning yellow and dropping off


This can be a natural part of the tree’s yearly cycle. All trees will drop leaves as they put out new growth (even the evergreen varieties, such as the Japanese Holly); the old is pushed off to make room for the new. A deciduous tree will drop most or all of its leaves in autumn/winter time. This is perfectly normal if the tree is deciduous (such as a Chinese Elm).

If your tree is dropping some leaves but you can see the tree is putting out new growth (new growth tends to be smaller and lighter in colour than the older foliage) then the tree is just dropping some of the old leaves to make room for the new ones – this is perfectly normal and healthy.

If all the leaves are turning yellow and dropping off, and it is not the time of year that you would expect a deciduous tree to drop, then there is something wrong and you need to take action. If this is the case the following could be the cause of your Bonsai’s upset:

  • Not enough watering – if your tree is drying out and not being watered enough it will often drop it’s leaves to try to stay hydrated as trees loose a lot of moisture through their leaves. Make sure you are standing your tree in water and allowing it to become fully saturated regularly. See info on Watering in the Bonsai Care Guide
  • Over watering – if your tree is not being allowed to dry in between watering and the roots are being kept wet all the time they will begin to rot. The tree will not be able to live without a healthy, active root system, so allow the soil to dry a bit before you next water and always check the dryness of the soil before you water from now on; only watering when the soil is no longer moist. Often a mould or fungus will begin to grow on soil that is kept continuously wet.  See info on Watering in the Bonsai Care Guide
  • Not getting enough sunlight – if your tree is positioned in a very dark or shady place it may not be getting enough light and will not be able to photosynthesize. If your tree is too far from a window or over shadowed by a large plant or object it might be affecting the level of light reaching your tree. If this is the case move the tree closer to a window or remove the obstacle obstructing your trees access to the sunlight. See info on Situation * in the Bonsai Care Guide

* Sometimes the light level is ideal in the summer months but by the winter, when the light is less during the day, the position of your tree may not be sufficient to get enough light to the Bonsai. If this is the case move the tree closer to a window or in to a position of greater light.

  • Hard water – if you live in a hard water area and are giving your tree water from the tap you will find your tree will only withstand this for so long. Eventually the roots will become coated in Lime (the alkali substance in hard water) which will stop the tree absorbing the nutrients it needs to stay healthy. Once roots are coated the leaves of the tree will go yellow and drop off. Avoid this situation by collecting rain water and only giving your tree this rather than the hard water from the tap (this is also the cheapest way to water a tree!) *

If you live in  place where you are unable to collect rain water there is a way to neutralise your hard, tap water; known as the ‘Vinegar Trick’.


The Vinegar Trick

  • Rinse out an old 4 pints milk container (or any container that will hold this amount of water)
  • Once rinsed – fill it with your hard tap water.
  • Now add 2 drops of malt vinegar (the kind you put on your fish and chips)
  • Replace the bottle lid and give the container a shake to mix the vinegar into the water.
  • Leave the water to stand for at least 24 hours (can be days and days)
  • When you return to the container you should see a collection of a whitish/grey sediment at the bottom of the bottle – this is the lime.
  • The water above this will be neutral, and can now be used to water your tree.



Leaves have gone yellow and/or brown and are NOT dropping off


If you can see no new growth and the majority of the leaves are turning yellow or brown then there is definitely something wrong and your tree is distressed. If this is the case the following could be the cause of your Bonsai’s upset:

Lack of water – The most likely cause of this symptom is that the tree is not being watered enough and is drying out. When the roots of the tree are not getting enough water regularly the tree begins to dry out; pulling the last available moisture to the base and roots of the Bonsai. This means that the leaves often dry out so quickly that they don’t even drop from the tree. If this appears to be the case with your tree it may need an emergency watering!*

* Emergency watering (also known as Plunge Watering) will require you to fill a container or sink with water and slowly submerge the pot in the water until the soil surface is completely covered. Once the pot and soil are under the water watch for air bubbles; if the soil is very dry there will be a lot of bubbles. If wet enough then very few bubbles will appear. Once the bubbles stop you can remove the tree from the water and position it back to its well-lit position. See info on Watering

Leaves are burning because of fierce sunlight – If your tree is positioned somewhere where it is getting mid-day sunlight it may be too intense for the leaves and will therefore scorch the foliage leaving your tree with many brown leaves. This is particularly likely if the sunlight reaching your Bonsai is coming through glass. If this is the issue then move your tree further from the window, or in to a slightly more protected place. If there is a position in your home or garden that offers plenty of light, but not too much direct mid-day sun this would be ideal. See info on Situation *

* Sometimes the light level is ideal in the winter months but by the summer, when the light is more intense during the day, the position of your tree may not be correct to get the right amount of light to the Bonsai and may Sun Scorch the foliage. If this is the case move the tree further from a window or in to a position of less fierce light.


Foliage appears to be covered in little insects


There are a variety of insects that may at times infest your Bonsai. Most of these are not life threatening and are just unattractive to see, but sometimes you may get a nasty bug that will require removal. Below are a list of common insects that you may find and what to do to get rid of them:

  • Green fly – These green aphids look nasty but actually they do very little permanent damage to your tree but they will cause a small strain on the plants nutrients. They usually can be found on the underside of leaves. To get rid of the little critters; a good and non-toxic solution is to use a mist sprayer and fill it with water adding just a small bit of washing up liquid. Then spray your tree thoroughly and leave on for about 20 – 30 minutes after this time rinse your tree off with water. Check to see that all the green-fly are gone/dead. If some survived repeat the process. Alternatively you can buy an insecticide to spray on your tree which will also kill the green-fly.
  • White fly – An Aphid species which may secrete a sticky substance which can be felt on the leaves. These creatures don’t like it wet – so if you think you have a white-fly infestation try spraying water on the under-side of the leaves. This might not remove the problem, but it will reduce the numbers. These are similar to Green aphids and are not life-threatening to your tree but they will cause a small strain on the plants nutrients. See above for solution.
  • Black fly – These are almost identical to Green aphids except they are black! They are not life-threatening to your tree but they will cause a small strain on the plants nutrients. See above for solution.
  • Scale insect – This pest is very clever and has developed a resilient cover that protects it from many insecticides. They appear like small brown bumps on leaves and branches on a tree. These can be individually picked off to remove them from your Bonsai. Alternatively you will need to find an insecticide that will specifically target Scale insect.
  • Red spider mite – These horrible bugs are very resilient and will require an insecticide to kill them off. It is important to spray your tree and only leave the insecticide on for a small amount of time (15-20 minutes is usually enough) then the tree must be thoroughly rinsed off with water. Red spider mites are nasty bugs and will do serious damage to your Bonsai. If you suspect that this is a bug your tree is dealing with; get an insecticide immediately and treat it.


We hope that this page has offered some useful advice. This information does not cover all potential issues so if you cannot find the solution to your problem, please contact us with photos :