by Terry Erasmus April 25, 2016 7 Comments

In the previous part of this 2 part blog post I wrote about some of the things you should be doing in Autumn. In this second part I will mention a few which come to mind as things you should not be doing.

#1 Do not repot any bonsai now

I am not sure why, but lately I have been receiving several emails and calls from people who want to know if I can repot their bonsai trees for them. Although this is a service which I offer, it is completely the wrong time of the year to be doing this.

The reason is simply horticultural. Trees are now changing to a state of dormancy, hence sap which was in the parts of the tree above ground are now moving into the parts below ground; the roots. It is also why feeding now is quite important, as I mentioned in the first part of this series. In spring this stored up energy will move up into the tree again and when you see buds swelling this means the sap has pushed up hard enough for the new growth to begin emerging. This is the perfect time to repot deciduous trees.

Were you to cut the roots now where will the tree store its energy? You may not kill the tree but it will be seriously weakened in spring and will take at least a season to recover. If you repot too early in spring the result will be less damaging but you will also limit the amount of sap which makes it to the branches and twigs and therefore the spring growth will be stunted.

Image caption. Hackberry or Celtis Sinensis is often one of the first trees to be repotted in spring as there buds begin swelling weeks before many other species. Notice the new green buds on the example, this is the best time to repot.

So do not repot now, wait until you see new spring movement on your trees and then repot. And please do not work to calendar months, watch the tree! The tree will tell you when it needs to be repotted, if you know what to look for. Read more about repotting here.

#2 Do not move your trees indoors

I cannot tell you how many people send me photos of dead or dying bonsai. After some investigation it emerges that the trees have been either kept indoors since they were purchased from the nursery or they are moved inside at night and outside during the day. I am not sure where the idea came in that bonsai are somehow unable to survive the outdoors but in fact to survive an indoors climate is far more challenging for a plant.

Although there are some more tropical trees which can be kept indoors, under the right conditions, all other trees should remain outdoors. Period! You can of course bring your tree or trees inside for special occasions and indeed when we exhibit trees they will often stay indoors for some days. Thats ok, but you cannot keep your trees indoors for an indefinite period of time, they will weaken, become sickly and very likely die.

Image caption. A bonsai tree, especially one like this Japanese white pine, may not be kept indoors for longer than a few days at a time. Bonsai should be kept outdoors and only brought indoors for short periods of time.

I don't so much blame the owner who did not, but perhaps could have known better. I blame the seller for not making sure the person buying the tree knew enough to keep the tree alive.

#3 Don't make large cuts now

This statement might seem to contradict something I wrote in the first part, however let me qualify what I mean.

Image caption. To make the most of cutting back a large branch, do it during the active growing period as a lot of back budding will be simulated.

If you have been using a sacrifice branch somewhere on your tree and you don't need it anymore, cutting it now ensures that sap is not directed there in spring and therefore not wasted as it can be used elsewhere on the tree. You can also maximise the full growing season to come, to assist in the healing of the scar (although with some species which heal very quickly such as Chinese maples, you may be better off cutting large branches in the latter part of spring when sap flow has reduced or the resulting scar tissue, or cambium will bulge a lot).

However if you are in need of growth where you currently don't have any, and you don't want to graft, then it is better to wait till the tree is actively growing again before removing larger branches. The act of doing this will undoubtedly stimulate back budding on branches but even on trunks, provided they are not too old. This will allow you to fill these empty spaces with growth which otherwise may never have developed.

#4 Don't neglect weeding

Image caption. Weeds such as this winter grass, if allowed to establish will take over your bonsai container and worse yet, the seeds will spread everywhere.

Some maintenance tasks are boring, some are especially boring. Weeding has to rank pretty highly on the boring scale in my opinion. When you have a reasonably large collection of trees it is easy to neglect weeding though, putting it off till tomorrow. This will be a mistake though as some weeds will be seeding soon and your problems will become even worse.

My method is as a tree comes across my table, after I have worked on it, trimming and wiring it, I give the surface of the pot a good clean. This might include removing the remnants of fertilizer, pieces of off-cut wire and weeding it thoroughly. A little brush is also handy for removing the loose bits on the surface and leaves your bonsai neat and tidy.

If you find a lot of liverwort, you should also remove it but it is an indication of a worse problem. Your growing medium is too wet. Read more about this problem in the first part of this blog.

#5 Don't forget to take cuttings

Cuttings are one of the easiest and cheapest ways to increase the size of your bonsai collection. There are many advantages of growing bonsai from cuttings; the roots all emerge from the same point, the characteristics of the mother tree is carried over, if it's a fruiting tree the bonsai grown from a cutting taken will soon begin fruiting also, and many more.

I find that taking hardwood cuttings at this time of the year has proven to provide me with a high rate of success. Ensure you take cuttings from trees with desirable characteristics such as leaf shape and size, good bark etc. Use the appropriate hardwood rooting hormone powder or liquid and be sure to use sharp implements such as a grafting knife when you work with the cuttings. Buy cutting supplies here.

As a rooting medium you can use mixes of Groperl, Vermiculite, Peat or even the already mixed Professional Mix. You want something which drains quickly but retains moisture or the tender roots issued by the cuttings in spring will dry out quickly. 

Image caption. A clay container with completed cuttings. Each one could be used to create a new bonsai or as grafting material to improve the roots of more advanced trees.

Right, so there are some don'ts. I'm sure there are more and if you can think of one please share it with us. Thanks for reading.

In the next blog I would like to share some images and explanations of some work I recently did on two Hackberry or Celtis sinensis. 





Terry Erasmus
Terry Erasmus

Author


7 Responses

ManRey
ManRey

May 04, 2017

Thank you Terry for this newsletter ! These Fall reminders are great. The subtle insights are proof you know your trees!
I’m missing my time in Hout Bay; now living in Texas.
Keep up the good work. MCS

Terry
Terry

April 27, 2016

Hi Joe, the reason your cuttings are not surviving is that there is nothing to keep them alive as there are no roots and there is no stored energy in the cutting. The dormant buds will shoot but then soon run out of energy. Taking the cutting earlier will help. My strike rate with maple cuttings, which others have told me are difficult, is about 80%. With regards to mediums it does not matter too much, just fast draining. Just don’t use something with compost or potting mix or any rotted organic material. Peat, LECA, perlite, coir, sand etc are all good though.

Joe
Joe

April 26, 2016

Thanks for the reply. I have only been taking hardwood cuttings for the last two years and I am still trying to refine my technique. My strike rate is very low. I took the cuttings in mid August. After placing them in the media, I noticed growth after about six weeks. Soon after that the new grows drys up and dies. This process of pushing new growth and drying occurs for a while before I get tired and throw them out. I will hopefully try your technique this year. Thank you.

Terry
Terry

April 26, 2016

Good question Joe. Please take note that I said “I have found” this to be a good time. You may find different. I believe it is as there is still sap in the cutting now and if you take the cutting much later there will not be any energy to push new growth in spring. What has your strike rate been? As to after care etc. I don’t have any. Treat with the hormone and plant. Leave the container in any position really as there are no roots nor leaves yet. In spring when you see buds swelling then you can move to morning sun, sheltered spot.

Terry
Terry

April 26, 2016

Hello Willem. Trees are not dormant yet. Autumn is one of the most important times to fertilize. In some trees is it is one of the ways in which to control growth, such as white pines. If you don’t fertilize your two needle pines now the spring candles will be weak. If you don’t feed a mature maple now then as you should not feed it much in early spring or you will ruin the ramification, it will only get its first food in late spring. So feeding now is important. Just curious, if you believed that trees are already dormant in Autumn then ask yourself why do leaves only change colour in autumn and where this energy goes to that was in the leaves. Thanks for reading and for your compliment, much appreciated.

Joe
Joe

April 25, 2016

Hi Terry. Great post. I am quite intrigued by No. 5. All this time I was under the impression that the best time to take hardwood cuttings would be in late August. However, I see that this is not necessarily the case. If I take cuttings now, would I have to store them in a greenhouse or could I just leave them outside? Then too, in the sun or shade? Thank you.

willem pretorius
willem pretorius

April 25, 2016

Thanks for the insightful blog Terry. One thing that confounds me is why one should fertilize now as trees are dormant. The fertilizer can not be taken up by the roots and in any case will be washed out before spring. By fertilizing now you will actually just feed the harmful stuff and not the tree. Or do I have it completely wrong?

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