Japanese White Pine Re-pot.

This then the penultimate in the series. I will be including a Scots Pine shortly. Both JWP and Scots have been heavily requested so without a further explanation I will get on with this one … a small Japanese White Pine (JWP).

Re-potting times do vary for the JWP, and on occasions I will wait until mid to late Spring. It is vital not to go too early with Pines; there are exceptions of course but this is greatly dependent on the level of post-potterative care you can provide.

As this one will be sheltered for the next few weeks I am happy to move to re-potting as candles show, but more importantly , that needles can be clearly seen within the candle.

The first images are of the new candle growth. The needles can be clearly seen.

Here is the tree in current pot. It is right and suits the JWP but is now too small. One important factor for JWP is depth of pot. JWP’s to benefit from depth of soil.

This particular tree has been in this pot for two years longer than it should have been. Root growth of JWP is not the same as conifers for instance; you will not find thick cream colour roots wrapped around and around the pot edges. The feeder roots of this species are much-much smaller.

Removal from pot is by standard methods, blade close to the inner edge, run all the way round, remove any securing wire then use a flat blade inserted down the side and lever upwards. I’ll say again; DO NOT just grab the trunk, pull and push and hope for the best! This is not how to release a tree from a pot!

The tree came free very easily. I purposely keep JWP’s on the dry side for ten days prior to re-potting. It makes the entire process simpler; both in terms of kindness to the tree and mess.

With the tree out I looked around the root-ball. I was hoping to see lots of white patches; which is mycorrhizal fungi. The symbiotic relationship between tree and fungi must not be over looked under any circumstances.

Mycorrhizae are much specialised organisms in the Order Glomales, which are found in close association with approximately 95% of all plants. (The name mycorrhiza comes from the ancient Greek for fungus and root.)

It is a symbiotic relationship where both organisms derive benefit – the fungus is not capable of photosynthesis, or to fix its own carbon, so it takes some of the carbohydrates, which the plant passes down to its roots. In exchange the plant receives essential nutrients and water from the fungus which has an extensive mycelium structure that reaches out further than the plant roots; it therefore forms a secondary root system.

They also assist the plant to withstand the stress of drought and prevent some of the soil-borne pathogens such as Phytophthora and Armillaria from entering the root system.

I was not to be disappointed. here is what I found.

It the last of these three images you can clearly see how dry I have been keeping this Pine. It does so make thinks much simpler. the soil just tends to fall away.

And finally I find the old securing wires. These I always release from the pot base after six months or so (depends on species). I do not however attempt to find the buried wire and remove. I wait until the next re-pot.

Here the soil that just falls away can be seen in my hand. Simply tipping my hand shows by keeping it on the dry side how little mess is left behind.

Using my trusty stainless steel ‘chop-stick I continue to probe gently away at the top and sides.

This is the perfect time to clean up any green algae and moss etc on the base of the tree.

Starting to look much better. Rather than just brush from side to side, brush from the trunk to the outer edge of the root-ball if you possibly can. Yes it takes longer to do but you benefit by combing surface roots at the same time.

I will over time thicken the base of the trunk up some. One area has a ‘wasp-waist’ in part.

With the surface roots inspected I am satisfied that no major crossing roots or decayed areas require removal. I have trimmed the sides by about 20%, no more. This is quite enough. JWP’s resent having too much of the fine feeder network removed in one go. You can if you wish work in sections and restrict removal to wedges; this then ensures sufficient roots remain to reactivate the new growth and continue to maintain the health of the tree.

Make notes what sections you do, then alternate during the next re-pot; which need not be left any longer than two years; re-potting again during the second year.

It was now time to work the base. I have found over nearly thirty years that Pines always put growth down below and have never found growth-shape on the tree affected by this in any way whatsoever.

The dead and decayed areas can be clearly seen here.

And after much tracing and removal of dead roots. All that remains now is some further trimming to the edges and I am done.

It is important to re-use some of the soil that has been removed. This is basically to reintroduce the beneficial fungi. I use a combination of sieve and hands.

As a JWP mix is such a gritty one it is a comparatively easy task to undertake.

So, new pot is selected. Initially yet again the pot I chose for this tree whilst in Swindon was not at all right. I had a reserve in mind which gave me about 18-20mm spare all round the edge.

It takes a while of course to select the soil that is going back into the mix, but this is a must. Fungi content has been set to one side so that I can make certain it goes within touching distance of the root-ball. I am going to add some extra by way of RHS approved ‘Rootgrow’™. Again when and if you choose to do this addition it must be in contact with exposed root ends.

My mix then is:

  1. Kiryu 40% is variable sizes. All sand sized is removed.
  2. Aqua-grit 30%
  3. Akadama 15%
  4. Propagating bark 15%

You’ll note I have a 70% grit content in my Pine. Despite thoughts from others that a high grit content is not helpful during freezing conditions, I have never found it to be a problem. Strangely, I moved away from such a high percentage of grit the last time around with this one and it is the first time I have had quite so much dead root.

So back to my own tried and tested then. In terms of additives I restrict this to:

  1. Trace elements, level 5mil spoon
  2. Frit, rounded 5mil spoon
  3. Iron, rounded 5mil spoon
  4. Miracle Gro organic acid loving. 10ml
  5. Additional M.Fingi.

With all suggestions I am just showing what I use and have always used. Well, to be fair MG organic is new (second year). You will see more recipes for soil make-up than you can throw a Nigella Lawson cook-book at.

All I will say is I have tried almost all permutations over the years, and will not move away from this recipe. I did last time and have dead roots as a result.

Here we are then, all ready for a good mix.

The soil I saved has been mixed in and M.Fungi I saved has been placed carefully around the roots. I’ve added some RG and again spend plenty of time putting my mix in until all unwanted air-pockets have been filled.

I have not laboured this area as it is covered in greater depth on other re-pot’s in the series. The tree was of course secured into the pot prior to filling with a soil-mix.

Top dressing is smaller particles of Akadama. I do this because it looks more pleasing to the eye; and easy to remove and replace once settled and weeds start to turn up.

I hope you have found something of interest in this short article; and as usual, please do contact me if you have any burning questions.

This bonsai will now stay in my green-house for between four and six weeks. Wind is your enemy with a recently re-potted pine; this way it stays well away from wind. During its stay, it will be warm of course but the GH has vents and shading. It will be misted daily and as soon as the top-dressing shows signs of drying (two to four days) I will water once again. Do not over-water, just keep slightly moist, no more and you will end up with a perfectly happy tree.

 

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11 thoughts on “Japanese White Pine Re-pot.

  1. ok Mike cheers for advice, maybe I could show you the white pine and you could let me know what you think of it sometime? as I am in awe of your white pine. Ill try buy some Kryo or Aqua grit then to use,

  2. I meant I have a Gorgous white pine to repot (and a few other conifers) in spring and I have a lot of Akadama and Cat litter, can I use these both as a substitute for the kiryo? as I live south Cumbria and getting anything to do with Bonsai is a bit of a hassle!

    • Yes, but do remember a JWP will appreciate a high % of lightweight grit, hence why I say Kiryu. Akadama is NOT a substitute as in a short time it breaks down as does CL. You will also get the ‘meringue’ effect using either CL or Akadama although not so significantly with Akadama.

      Run with a lightweight grit, mix this in at around 60-70% then the balance with sifted Akadama (remove dust). ENSURE you do not have a soaked mix during winter months; come to that make certain it is not soaking at anytime.

      If I can help just shout.

      Mike

  3. May I ask where can you buy Propagating bark and Aqua grit? do magor retailors like BnQ sell it? and is it ok to use 55% AKADAMA as i cant get hold of any Kiryu :/

    • Kiryu is available from most bonsai nurseries. Melcourt retail the propagating bark; Aqua grit is made by a company called Underworld Products. Your question on Akadama is a bit open; in relation to what exactly?

      Best wishes

      Mike

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