by Terry Erasmus July 29, 2015 3 Comments

You may have done all your winter bonsai tasks already but I have prepared a short list of some of those which I think are important and apply to most bonsai artists.


By now I am sure you all have done whatever pruning you wanted to do. Remember not to prune branches which are being used as sacrifices or that still need to thicken at the base. Pruning them would be counter-productive. It's also not a good idea to prune large branches in winter, assuming you are wanting back budding (buds which form further back along a branch or trunk which you can use in your design as future branches), its better to do this during the active growing periods. Pruning in winter when there is no sap flow is also not conducive to callousing over or healing of the resulting cut scars.

Weeding before its too late

Weeds love this time of the year, at least in the Western Cape as we are a winter rainfall area. Be sure to weed as soon as these pesky plants begin to grow, or you might find they get out of hand before you know it. I find its a good idea to walk around with a bucket and throw the weeds into it as you go through your trees. Otherwise these weeds are thrown to the ground and simply grow there and seed, becoming an even worse problem.

Too much moss

Everyone loves moss, including myself. Moss makes the ideal bonsai tree ground cover. However if you live in a wet and cold area moss will proliferate and envelop the entire surface of the pot and will result in greatly increased water retention, which in turn may lead to root rot or other problems. Best is to keep moss to a minimum, at least for most of winter, allowing it to develop if you want, towards the end of the season. It is rather important though that you remove all moss from trunks, this will irreparably damage the bark, as it causes it to rot.

Its a good time of the year to collect moss though as there should be a lot about. Look in forests, along rivers or fountains, even along the roadside! Try to find different mosses which you combine around your trees for a little variety, as depicted in the image below.

Image caption. I think there is a perception that moss is grown year round on bonsai trees in Japan. In fact although there may well be some moss which has developed on a tree which has not been potted for a number of years, most of the times when you and I see moss on trees on exhibition, that moss has only days before been placed there.

Select trees for repotting

Identify trees which need to be repotted in the coming season. A couple telltale signs of a tree which needs a repot:

  1. Some trees may be pushing out of their pots, such as maples or elms. Chinese maples, as shown in the image below can rapidly fill a container with roots.
  2. Other trees might be showing signs of weak growth and need to be revitalized. Pruning their roots will often initiate a growth spurt.
  3. Most importantly look for growing mediums which are not draining well, these trees must be repotted.

Image caption. Some species need more frequent repotting than others. Chinese maples can fill a pot in a single season whereas most conifers need not be repotted for many years.

Don't simply repot because it sounds like the right thing to do, or because everyone is repotting and you feel left out. Repotting too frequently results in more bad than good.

Preventative Plant Protection

Lime Sulphur is the one spray I highly recommended for applying in winter. It is ideal for preventing over wintering of common pests and fungi. It may be used on deciduous and evergreens bonsai trees. It is a highly effective fungicide solution which controls anthracnose (blackened growing tips affecting new leaves on deciduous trees especially maples), Mealy Bug, Mites, Powdery Mildew, Scale and Wooly aphids. Repeat application 2 weeks apart and use the entire bottle as it has a very short shelf life and cannot be stored once opened. You can use a dilution ratio of 1:10 (Lime sulphur:water)

Image caption. Lime sulphur is a very versatile spray to prevent the over-wintering of many pests and fungi.

Leave any comments or suggestions in the space provided below. I'd like to hear from you.

Terry Erasmus
Terry Erasmus


3 Responses

Kyle Ravenell
Kyle Ravenell

September 03, 2015

The best rooms to keep indoor bonsai in tend to be kitchens and bathrooms due to the moisture from the taps and sinks. Keeping the tree on a drip tray will allow some water to sit under the pot.


August 08, 2015

Hi Chris. Very good questions. For any pesticide I would stick to the guidelines for dilution on the instruction leaflet. There is no reason to increase or decrease the concentration because it is a bonsai tree. Off hand I do not know what the dilution ratio is, I’d suggest just to look at the instructions. Koinor is never to be used as a spray, only a soil drench as it is systemic and all systemics are absorbed through the root zone.
Whether lime sulphur is better than Koinor for scale is not really something I’m able to answer. If you can spray lime sulphur ie during dormancy then that would be what I would use as it will help for a lot of other problems, especially those which over winter. If during the growing season as the problem tree is deciduous then using something systemic is very good for all sucking and chewing insects.
Good luck!

Chris Jankovich
Chris Jankovich

August 07, 2015

I have discovered scale and ants on one of my Bonsai plants. I live in Hilton KZN.
One of the treatments for ants is a bath in Koinor 350 SC. Please advise what the mixing solution is for say 5 litres of water, or whatever mixing ratios you have available. Can the Koinor be used as a spray against the scale as well or would lime sulphur be a better bet.
Many thanks

Leave a comment

Comments will be approved before showing up.

Current Tree Talk

Seasonal Work on an Upright Hackberry
Seasonal Work on an Upright Hackberry

by Terry Erasmus June 20, 2017 4 Comments

At the end of each growing season deciduous trees need to be worked on. The tasks which need to be completed include removing the dying leaves, cutting back twigs where needed, wiring and general assessment of the trees development over the past season.

Read full article →

Kusamono Appreciation
Kusamono Appreciation

by Terry Erasmus May 22, 2017 1 Comment

Kusamono is essentially a planting which may consist of anything including grasses or flowers. The material used in Kusamono plantings are often free; you can collect them growing just about anywhere if you go for a walk. You may find many of the plants suited to these plantings are even considered weeds!

Read full article →

8th World Bonsai Convention, Saitama, Japan. 2017
8th World Bonsai Convention, Saitama, Japan. 2017

by Terry Erasmus April 28, 2017 1 Comment

Japan hosted the World Bonsai Friendship Federation Convention, after a period of 20 odd years. We were spoilt with 3 days of bonsai of the highest standards. A huge draw card of the convention to local and foreigners alike were the 300 some top class bonsai on display.

Read full article →