“When we long for life without difficulties, we should remember that oak-trees grow strong in contrary winds; and diamonds are made under pressure”
This then, the first of a series of re-pot’s, mostly aimed at the new enthusiast or perhaps anyone interested in taking up the art of Bonsai; and I sincerely hope you do!
This Hawthorn Bonsai had been in its current pot for some four years, which is too long. Circumstances of one type or another prevented me from repotting in 2010; thus it is overdue and ready for a new home. This particular Hawthorn is usually re-potted every second or third year.
Before I explain the process of re-potting, it would be prudent at this stage to say why a Bonsai should be repotted. In essence, they can become pot-bound. That is, the roots of the Bonsai become cramped and form a tightly packed mass that inhibits growth and may well weaken it; at worst, cause it to die. As well as the supply of water being radically reduced to the leaves, needles etc, very little in the way of nutrients will be able to get where they are required during the growing season.
Additionally it gets extremely difficult to water, you may feel you are watering the tree well – but the water will only likely be wetting the surface soil. To remedy this problem you can immerse the pot containing the tree into a bowl of water, bubbles of air will come to the surface as the water fills the pot. I have only ever left it standing in the bowl for a maximum of fifteen minutes; this has always been ample time to water well.
When removed from the bowl of water, hold the pot with both hands and tip slowly from side to side to drain excess water away. You will likely need to do this several times until no further running water is seen coming from the pot bottom.
When a Bonsai is extremely pot-bound, roots die back on a regular basis, and if room is not available for new feeder roots to form, then you can see the slippery slope!
It is not necessary to choose a larger pot for your repot; unless of course the Bonsai has out-grown the current one, or you would simply like a change.
You will see when researching the subject of re-potting either via the web or with books, some will suggest an autumn repot. Personally for almost three decades I have conducted all re-pots from approximately the third week of February to the end of April, and in some cases with Pines, Junipers etc the first week of May. This is based on weather climates in the SW of England. Besides which mandatory protection is a must if you insist on autumn time. If re-potted in Autumn you will have to keep the newly re-potted tree virtually frost and wind free until spring.
UK winters of late, 2008-2011 have been much colder than what was the ‘norm,’ it makes sense to me to use the new growth season from late winter to early spring to help the tree along in its new growth process.
Once the buds are well swollen but before leaves open – is your optimum time for deciduous species. I will cover Evergreens in a separate and related article.
So, having established the Bonsai is due to be re-potted and that the time is right, a few basic steps should be taken.
Have everything ready to use before removing the tree from its pot. I use a variety of tools and soils; it is not however set in stone what you must do and my article for the English Hawthorn is intended to be a guide only. Geographical placement, tree age, type, soil make-up, all vary, so you must do what works for you. I am showing you what I do and what works for me; creating a healthy and happy tree.
On tools, I have a selection of knives that I use; mostly for running around the edge of the pot to free the tree. In some instances if I feel a slice of the root ball has to be removed from the very bottom I use the serrated knife shown on the left. This is extremely sharp and great care must be shown to protect yourself from cuts … or worse.
These are laid out ready by my work-station. I also have a variety of tools such as root-hook, ‘chop-sticks’ etc for working directly on the root ball.
In addition I have other tools that assist the re-potting process. The small scoops are used when filling the pot with new soil medium. The larger green scoop I use for measuring each element of the medium and then to mix.
I use this Japanese product to seal all large cuts I make to the root system. Just squeeze a small amount onto the finger and smear across the cut surface.
Viewed from the left; Japanese cutters for removing large roots. Root pruning scissors, wire cutters.
The first-thing to check for – is any retaining wires that may still be in place. Simply snip these at the underside of the pot as close to the drain-hole as possible.
To remove a tree from the pot can be challenging at times; especially when it has been in the same one too long! Take a sharp knife or a tool similar to the one that can be seen above and score to the base of the pot all round each edge. I then use a firm wallpaper scraper and slide this down the edge of the pot, with a piece of rubber between the blade and the pot (to protect the pot edge) use an upwards levering motion all the way round until you can grip an edge and lift away from the pot.
The obvious movement is to hold the trunk and bend and twist to remove it, this can damage the bark, and worse still those precious roots the Bonsai has spent so long growing. So try to avoid pulling from the trunk.
With the tree removed and the pot put safely to one side – this is the view looking at the base of the root-ball.
I have started to ‘comb’ out the winding roots; measuring the length it is just short of 1.3 metres from the soil to the tips. This as with most elements of a repot is a fairly slow process. Carefully using whichever tool works best for you, tease (not tug) the roots away from the edge. Some will break away which is quite normal so don’t panic.
Keeping the tree drier than normal for a couple of weeks prior to repot will make the entire process far easier and less messy. Not bone-dry, but barely moist.
You can see here I am using a Japanese chop-stick to gently tease the ‘beard’ outwards away from the root ball. Don’t simply drag across the root-ball, work from the centre base outwards and gently pull out the long beard. Rasputin would have been proud!
As well as the roots – this is an ideal time to do intensive weeding. As can be seen in the following image, they are growing well; don’t they always?
I have decided to remove the long beard of roots first then carry on with the upper soil level. You can see I am using the very sharp root pruning scissors in the following image. I re-sharpen after every root-prune. I am fortunate in having a specialist jig which removes almost nothing and hones a razor sharp edge. This is important as you want to cut precisely rather than a crushing cut which damages greatly any remaining root ends.
It is now time to start work removing the weeds whilst at the same time inspecting every part of the root ball very closely. I am looking for any bugs that ought not be there and checking general health and overall condition of the root-ball.
I use tweezers with pointed ends. I have honed off the point to be more like the point of a ball point pen … slightly rounded. Here I have located weeds and sink tweezers in and down and grip the weed, removing not only weed but all of the roots it had put down.
Whilst this may seem a long and laborious job it only actually takes a few minutes to remove every single weed; this procedure also facilitates ease of reach around the trunk base .
In the following image you can clearly see that moss has previously climbed the trunk. This was removed, but unfortunately not before it had softened and rotted the bark immediately under it, so be warned, it may look pretty and natural but damage can occur. On the Hawthorn it looked so attractive I sadly left it on too long. You can see the damage that will take a long time to repair. And for once my local fleet of Blackbirds let me down.
The green brush to the left of the above image is used to brush away all algae that is stuck to the trunk and root tops. This is your one major opportunity to be thorough and get into every ‘nook and cranny.’ It is never so easy once potted up. Especially once potted, because the Bonsai should not be disturbed ….zzzzz NO not that type, I mean physically disturbed!
Here you can see some hidden remaining wire left over from when the old retaining wires were cut. Just pull away gently.
With the bark and root surfaces cleaned, all roots that had been wrapped around the inside of the pot removed I am now going to wash the root ball with a garden hose. I have a gun fitted that offers several differing spray patterns. I am using the jet as can be seen. I am washing through the top, sides and underneath very thoroughly.
This will in effect open the root ball further, wash much old soil out and remove any dead roots. They simply wash off. When complete the root ball will have a slight ‘see-through’ element which will help with on-going watering and air requirements.
It is now time once the root ball has stopped dripping to inspect underneath. My intention here is to cut away any roots that have grown from the sides and curled back on themselves to underneath. I do this so that branches above do not emulate growth and future movement on the twisted nature of the roots in the pot. This will permit me to gain full lateral expansion and a more pleasing shape above. I realise the shape will and can be changed with wire. But why not give the tree a chance before moving everything with wire?
Here you can see I am slowly working my way across the root-ball removing those that have grown underneath. Should … while you are on a roll, an interruption occur such as the phone; simply wrap the root ball with a damp towel. Make certain it is an old one and not straight from the bathroom or you’ll be in serious trouble:-)
My root ball is now as prepared as I wanted. This is not what is known as a bare root repot; it is just simply thorough. I am satisfied that any old and bad soil has been removed, surplus roots have gone and it is now ready for the pot. On this occasion I am not going to correct some of the visible surface roots. I have intended this repot to be suitable for beginners. further advanced techniques will be demonstrated on re-pot’s coming up over the next few weeks.
Soil is a huge subject and later on this year I will have a full article dedicated to soil. For this then I am using several products to make my soil medium. You will also note I have not mentioned making up my medium as yet. I prefer to wait until the tree is fully prepared and I have been able to judge the current health; once I have established said health I will then and only then tailor the mix specific to the tree as is now. Many beginners I speak to always ask if the ‘Bonsai’ soil sold in supermarkets and garden-centres is suitable? Short answer … No not really. It is little more than ‘a’ soil with added grit. You have no idea of the pH content or where it came from. My advice, don’t bother. Basic soil mix however from specialist Bonsai nurseries is a different thing all together and many nurseries work extremely hard in creating a one shot basic mix that suits most species. You can then add as you wish to customise it further.
First up is Akadama, a baked clay granule – obtained from Japan through local Bonsai nurseries. I am fortunate to have it delivered directly as I take a pallet at a time.
The bag contents are sieved and graded. All dust and tiny granules are discarded for repotting purposes. An English 5p coin is shown in the following images for comparison purposes. The larger particles are used at the base mix level. The smaller is used more towards the surface. Akadama is surface mined, immediately sifted and bagged, and supplied in various grades: the deeper mined grade being somewhat harder and more useful in horticulture than the more shallow mined grades. In latter years I have found wastage absolutely minimal.
Next up is sifted and graded propagating bark. The only organic product as everything else is inorganic. I have tried many barks over the years and have settled with this particular one, which I will cover in greater detail within my forthcoming article on soil specifically.
I use three types of ‘gravel’ or stone. One is Kiryu this is a Japanese imported mixture which is made up of clay and pumice. It can be used neat – or mixed with other soil mixes. Kiryu allows for good air circulation which assists in the promotion of a strong healthy root ball.
When I sieve and grade Kiryu, the smallest particles are very sandy in texture and I am going to use a percentage of this sand in the Hawthorn mix. Various sizes are show below that I have separated by sieving. I have used the Kiryu as a sand base for many years and find that many species thrive on it. You need to be careful of course to get quantities perfect as blocking the free-draining soil concept is not what I am advocating. It is however all about getting the balance right.
Finally a product that I started using when Kyodama went out of production; although if you are interested Kyodama is now available again. I am however staying with this particular product which is called ‘aqua-grit,’ pH neutral, and great for holding nutrients. Small and large shown below. I have been so pleased with this product. I still sift to remove dusts of course.
Finally a rounded grit. I like to have a combination of coarse and rounded within my mix. Each generates a slightly different root configuration. One cuts and splits, the smooth permits ‘flowing growth’ above.
It is at this stage that I will make a choice on soil type and percentages. I may wish to have the Hawthorn very free-draining, or even a higher baked clay content. I am however sticking with what I had in mind before I started repotting as I found nothing within the existing root mass to give me any cause for concern.
I am on this occasion using 50% Akadama, graded sized particles, 20% mixed Kiryu plus sand content at 1 and 2mm particles, 20% Aqua-grit, a nutrient holding gravel that I now use in place of Kyodama, and just 10% propagating bark with some finely chopped sphagnum moss used in the first soil going near the roots. I have no scientific knowledge on SM but I am certain the healing properties are well documented should you wish to research further.
It is now time to select a pot and start off with preparation. I have decided to move away from tradition and run with a round lightly glazed green pot which I purchased on a whim with no tree in mind to sit in it. I would most certainly not normally consider semi-glazed for a Hawthorn but as the tree is several years away from showing I can indulge my fancy somewhat.
As this pot is slightly deeper that the original I am going to have a layer of grit in the bottom to aid water drainage. In smaller shallower pots a grit layer is absolutely not required. Do not therefore imagine you need a grit layer with every single pot. You do not. Medium to large particles are fine as a base layer in pots not so deep.
My pot requires some preparation first. I need to cover the large drain hole with some mesh and tie that in. The following pictures take you through the procedure.
You can see my mesh is fitted and suitably secured. I have also fitted strong twine which will secure my tree until the roots are strong enough to take over. You can use wire if you wish but now I am retired I try to make every piece of wire count; it is quite expensive these days.
Drainage layer now covering the pot base.
Next I am mixing my soil. Also included within the mix is a small amount of Frit and Trace Elements. I actually prepare two lots of soil medium, a small amount initially so that I can manipulate this in and around all the empty spaces.
You can clearly see from the above image that it is an open mix that will drain well and allow new growth to copiously fill the pot over time.
After selecting my pot and going through initial prep work it is time to put the tree within its new home. Before I do this I will include a layer of soil mix first for the tree base to sit on. Prior to actually getting the tree in the pot I hold the tree upside down and by hand drop soil onto the base in a sprinkling and tapping nature so that I am not relying on a wiggle which is coming up. No not me wiggling … the tree!
Here then the tree is placed to check on height and position. I am aiming for slightly off centre and the base of the surface roots just and only just above the pot rim.
At this stage put the flat of each hand on the root ball and wiggle it just a few mm to the left and right. This will put the soil medium all round the base and ensure no pockets remain. Yes you need space for air and there will be more than enough when complete. This movement is to eradicate larger spaces that can form.
Once satisfied the tree is positioned correctly it requires tying in. Take the twine and find locations to tie off. When I have no choice other than to cross large roots I will suitable protect the root with clear tubing as can be seen here.
It is now time to start putting in my initial mix. This part of the process must be taken slowly and methodically. DO NOT be tempted to rush this stage, it is crucial you work the soil into and around the root ball. I use my stainless ‘chop-sticks’ the wooden one and my forefinger and index finger massaging as I go. Keep dibbing and tapping the side of the pot as you go. The soil will with the slapping vibrations drop into all the empty spaces.
Thus far this has been the longest part of the process. I am now satisfied the soil is as it should be and slightly below the pot rim. I will now pour a finer sieved Akadama to use as a surface dressing. This looks better and when and if weeds become a problem later on, or next year even, you can simply remove this dressing layer and replace with a fresh one.
All that remains now is to water the tree in using a watering can fitted with a fine rose. The Hawthorn will go into a protection area, out of direct sun, wind and any frosts. After about six weeks or so, I will return it to my display house. Prior to this I will have left it outside still sheltered though to aclimatise to outside weather rather than going straight from sheltered to the outside elements. I am currently trialling a new organic root stimulant to be used with the initial watering. It is too early to tell but I shall divulge and report back later in the year with updated Hawthorn images.
No feed should be given for at least six weeks, ideally eight to ten. I will not water the tree again until I see the top layer of akadama drying or when I know the tree is taking up water. This is crucial, the tree will become lazy if you continually water. You need the new forming roots to work and search out moisture.
I will overhead mist the buds/leaves twice daily to lessen the load on the roots. I will do this for three weeks. One should be mindful though of mildew. Hawthorns can be susceptible.
Here then is the finished soil surface. Ignore the twine guy ropes, as it is not to be an exhibited tree just yet, I find this is just as suitable as wire guy lines. Extensive work to the this tree will take place after recovery and possibly not for at least four months. I want the tree to recover first.
As a final aside to this repot I have included some storage ideas that I currently use. Even old Horlicks containers come in handy. The plastic tubs cost a whole £1.29 each from Morrisons, and are air tight, keeping products from getting damp. These are available in many different sizes. I use old Omega fish oil pots and even old cologne tins; these are excellent with a hole for keeping twine in.
Spray bottles should be clearly marked not only to prevent incorrect use but also should a child gain access and spray any. It is always advisable to keep a copy of any chemical analysis sheet in a draw close by. The simplest solution is to keep things well away from young curious eyes. Tools are razor sharp and can be quite dangerous to children.
Finally just a few other assorted tools and equipment that will assist you. As time goes by you will increase your arsenal of equipment; so take time on choice, they will be with you a long time. The first image is my sieve with interchangeable grills.
I use a variety of heat torches mostly for cleaning jins and when steam bending.
And really, here is finally the last picture in this article. I’ve included it because I am always asked why it is with all my Bonsai ‘stuff,’ yes, it is vinegar, not sarsons either, I use a dribble in a watering can from time to time on acid loving species.
Thank you for looking and I hope you have found something to assist you. Just remember, it is not an onerous task, it should be an enjoyable one. Please do not hesitate to contact me for further information.
And after a short wait with careful post re-potting care, the Hawthorn has produced a wonderful array of flowers for me to enjoy. Further work for this tree once flowers have faded away. As of 25th April 2011.