Through a series of photographs and short notes I will take you through the repot and root prune process used for one of my Chinese Elms in Spring 2018.  This process is the same I would apply for any bonsai that has outgrown its container.

Step 1 – Observation of the bonsai

The tree is sitting very high in the pot suggesting the roots are now pushing it ‘up’ from its original placement.  With Chinese Elm it is not uncommon to have to repot annually due to their rapid root growth.

I also noticed that water ran off the surface without much absorption and the lower soil was remaining dry and crumbly.  This is an indication of poor percolation / soil breakdown.  This reduces the ability for oxygen and water to interact with the roots.

Step 2 – Exposing the rootball

Take your time to remove the tree from the pot (don’t foget to remove the ties first!).  Slowly tease away the soil mass to identify the primary rootball.

Make sure you have a spray bottle on hand to keep misting the fine roots.

Take care not to cause unecassary damage to existing roots.  A chopstick is the ideal sorting tool.

Step 3 – Start sorting out the root structure

Using a chopstick I begin to remove the soil and other matter that binds the roots together.  Carefully beginning the process of untangling the fibres – some will tear (do not worry)

I examine the roots for signs of disease. (They often smell or squash easily)

Watch out for any bugs or larvae that may be wriggling about – try to identify and eradicate. GET ADVICE!

Step 4 – Time to do some root pruning

Once fully untangled it was possible to establish what  I really needed in this mass of growth.  I identified the core networks of roots I wanted for my tree – removing the rest!

In this case I have removed at least 1/2 of the lower root growth.  New roots will emerge from the cut sites.  In this way it is possible to develop a ramified system.

I have  removed  crossing roots and unwanted large surface roots.  I keep misting the roots to keep them wet whilst I work.

Step 5 – Prepare the pot

I have cleaned the old pot and checked for any winter damage.  In this case it had a hairline crack so I changed it.  Nothing worse than having a pot crack open in winter – risking root damage / death.

I have put a plastic mesh across the drainage holes to reduce the chance of insects getting in and grit getting out.

I then layed down a thin layer of cleaned grit as a base for the bonsai soil. This can reduce water collecting  causing root rot…

Step 6 – Prepare tie wires and soil bed

I cut two lengths of wire for anchoring ties and thread them through the drainage holes.  As the elm has lots of gnarly old roots beneath the surface I will use these to hold the tree in place.

I added the bonsai soil to the level I wanted the tree to sit at and ‘mounded up’ at the position the trunk will be placed.  This is the time to re-check the root and tree fits the pot.  I was aiming for a good radial surface spread and wanted to allow space at the edges for more root growth.

Step 7 – Position the tree

By now you should be happy where the tree will sit.  This is not a process you want to repeat unless you have to – it stresses the tree and can slow/stop growth for the year.

Secure the tree into position with the wire ensuring you avoid future damage to surface roots – wire digging in as they expand. I slide the wires beneath the lower ‘hidden’ roots or use a wooden peg system.

Step 8 – Fill the pot with soil

I gradually added soil to the pot whilst working it into the root network with a chopstick.  Slowly trying to fill any air pockets in hard to get places.

This is the last opportunity to identify and remove any unwanted upward growing roots.  So keep your clippers handy…

In this project I have added a rock and wrapped some of the roots around it to provide interest.  Over the years I hope that it will become gripped by the expanding roots.

Step 9 – Water and Detail

Water the tree carefully until it runs out of the bottom of the pot clear.  Free draining soil avoids the risk of water collecting and risking root rot during this critical early stage.

Check for any final alterations – you can still move the tree if needed.  Make certain it feels secure. You don’t want new root growth breaking due to insecure tie downs.

Brush away unwanted soil from the exposed roots and apply a moss top dressing. (See later blog post)

Step 10 – Admire your work

Take the time to admire what you have achieved – well done!

I make notes in my bonsai diary with a bring up date for the next ‘planned’ repot.  This tree will be fine for at least 3 years but I have a review date set for 2020 (2yrs)

I will not start applying fertiliser for at least 4 weeks or until any new growth starts hardening off.  As an indoor tree you can repot throughout the growing season without much risk.  I avoid winter as my indoor elms go dormant.

If you wish to purchase this tree then send me a message or look in the shop section.

In Part 2 of this Bonsai Collaboration I root prune and pot my four collected field-grown trees.

Watch to see just how much root growth you can remove safely.  I ended up with two Smooth Leaf Elms and two European Hornbeams.

Jelle @GrowingBonsai  also pops in for a few more words of wisdom…

Topics Covered today:

Cleaning and root pruning the first tree.
Why can we prune so much root?
Into a pot.
Let’s look at the Hornbeam.
Some essential advice.
What can I do with this Elm?
A root cutting perhaps?
Another tree to pot up.
A disappointing Hornbeam.
Jelle has the last word.

God Bless & Happy Bonsaiing Xavier

The past few years have represented a steep learning curve for me when it comes to bonsai care and development.  So it came as no surprise to discover that my care of Azalea was at best ‘prehistoric’ in its application.  In truth, I knew that azalea were acid loving and needed ericaceous soil…so that’s what I’ve mostly used.  I purchased 5 or 6 young nursery stock azaleas in 2015, pruned them hard and then potted them in this ericaceous mix.  Of course I have since discovered that though the soil was okay, my timing was abysmal for the rest of the activities. Thankfully, the young trees survived…till now?

I am currently doing an online course and have discovered a great deal about Satsuki azalea…which really just flowers a little later than others.  They derive from the combination of two types of  Rhododendron and there are 1000’s of species – based on flower colour  (a lot like roses).  This year I was keen to understand more as I had taken receipt of 7 Satsuki from China.  The first lesson was crucial to understanding why my garden centre trees were not thriving.  They were probably in the wrong soil for optimal healthy root growth.

I had heard of Kanuma but thought it was just another expensive variety of Akadama.  In fact, it is a very ‘soft’ potting medium (looks like akadama) that breaks down very easily and is perfect for the development of fine roots produced by an azalea.  Azalea are bushes and do not easily develop strong nebari or strong, deep  roots.  Instead, they grow a fine mesh of shallow roots very near to the surface.  Heavy soil will severely restrict growth and hence restrict the development of your tree – this was my problem.  Opinion still remains divided on soil, but this year I took the plunge and invested in some Kanuma. (Downtown, Grantham, is selling some at the moment for a reasonable price)

The imported Satsuki were potted in a cheap transporting compost so would need full clean outs.  Ideally, this process would have been done even earlier in the year but I only completed the lesson two weeks ago

I have included several pictures of the root clean and pruning process I carried out.  All of the trees are relatively young and have yet to develop any true sheen (core root structure) beneath the trunk.  Under normal circumstances you would leave the sheen alone – unless it looked black and/or ill.  Azalea are prone to dying when you do ‘stuff’ to them at the wrong time or in the wrong way…

So over the past 3 days I have been out servicing my azaleas.  Firstly, pruning out all unwanted growth – reducing the 5 shoot clusters to just 2.  I also removed any flower buds to reduce the stress on the trees this year.  Much that I would have loved to see some flowers…I would prefer to see the trees survive the repots!  If all goes well then next year should produce some decent displays.

With the roots cleaned and trimmed I prepared the new pots. Another learning point was that these fine roots are sliced very easily by anchor wires.  There are many methods to avoid this damage but I have settled on using electrical earth sheaths which I slide onto the wire.  No merit points for beauty but it was all I had to hand. In another year I will probably try to remove these – if the root structure has developed sufficiently to hold the tree in the pot.

Once tied in place I carefully chop-sticked the Kanuma into all the air pockets and watered thoroughly.  Beware – Kanuma is very soft and will crush if you try to press it down with your fingers. Gentle does it! ALSO – wear gloves; as the soil sucks the moisture out of your body and cracks the skin.  Which leads me to my next point: use moss to cover the surface to help retain moisture.  These trees love water but actually benefit from being left to dry out for 2-3 days.  Allegedly they are lazy root developers and hence need a little ‘encouragement’ to go seek water further afield in the pot!!

I have placed the trees in the greenhouse where they will stay until they show signs of new growth – they are delicate at this time so need tender care…and no wind.  They do love misting and I will certainly be doing that each day for the next few weeks.  In about 3 weeks I will start feeding them heavily with organic bio gold lumps.

To this end, it is also important to recognise that you keep a good ‘fingers gap’ between the edge of the pot and any roots – they will scorch and die in hot sun (another good reason for moss).  Azalea also do well in deeper pots and you will generally discover that half of your pot depth is just soil – but it does provide a good water reservoir and heat sink during the summer.

If you see yellowing leaves – don’t panic.  The heavily calcium water (in this area) can cause this discolouration.  Easy solution is to sprinkle some Epsom salts onto the surface.  If you witness branch dieback then you can be worried.  Branches are ‘root specific’ and this will most often indicate signs of disease beneath the surface. This is when you must carry out an emergency repot and inspect the roots. It should be apparent where the problem exists (look online for what sick roots look like) – cut them away.

As a final point – the flowers make the effort worth it!  Though you really ought to remove them all within  a week of full bloom if you want your tree to remain healthy.