Azalea bonsai repotting
The repotting of azalea bonsai (Rhododendron indicum, Satsuki azalea) is one of the important measures of bonsai care and must be carried out every 2-4 years.
Healthy azalea bonsai root through the bonsai pot more or less quickly.
Important, tiny cavities in the bonsai soil are quickly filled with roots. The bonsai soil is compressed and the air and water permeability of the soil decreases.
However, the bonsai trees urgently needs a well-permeable soil in the pot. Otherwise first the root growth and later the growth of the entire bonsai would suffer.
Young, fast-growing species (eg. Maple, Chinese elm bonsai) with strong root growth usually have to be repotted after 2 years. Older trees, especially conifer bonsai, can often spend much longer in their pots. They root through the substrate more slowly.
When repotting bonsai, in most cases a root cut is carried out to reduce the root mass and increase the fine branching.
In this article, we show the basic steps that have to be taken when repotting an azalea bonsai.
Step by step
1. Remove fixation wire
If the bonsai has been properly and professionally potted a bonsai wire for fixing the root ball was used. This fixation wire must be removed before repotting of the tree can start.
The best way to do this is to cut the fixing wire on the downside of the bonsai pot with a bonsai wire cutter.
2. Remove bonsai soil
A root claw with 2 or 3 tines is usually used to remove the old bonsai soil. If the substrate is already very solid, a root hook is more suitable.
3. Clean the trunk base
Bonsai that have been in a pot for a long time often have moss on the trunk base. When repotting you can use the opportunity to remove it with a brush. At the same time, the root base is exposed to see if anything needs to be corrected.
4. Correct roots
Stronger (no longer needed) roots are best removed with an bonsai cutter. The best way to do this is with a root cutter or bud forceps.
Use these bonsai tools only for work in the root area. Due to the fine stones in the substrate, these tools quickly become dull and should then no longer be used on the above-ground part of the tree.
5. Place the repotting mesh
In order to prevent the soil from trickling out of the drainage holes, plastic potting mesh are placed inside the pot.
So that the bonsai can grow well, it is important that the root ball is fixed with wire. Bonsai wire is passed through the wire holes (found in most handmade bonsai pots) in the way shown.
If there are no wire holes, the fixing wire can also be inserted through the drainage holes.
6. Fill in bonsai soil
Before the root ball of the Satsuki Azalea can be aligned in the pot a little bit soil should be filled in.
For azalea bonsai a substrate with a very low pH value should definitely be taken. The Kanuma bonsai soil, a substrate especially for azaleas, has proven very successful. It is imported from Japan.
Peat substrates are also very sour. But they are (except perhaps in the cultivation phase) not suitable for finished azalea bonsai. The main disadvantage is that once dried, peat substrates are very difficult to remoisten. And ball dryness doesn't like an azalea bonsai to come through.
7. Determine position
Now we can start potting. Before we fix the root ball we determine the position and the potting depth. Here in our case, the azalea is not deep enough in the pot.
8. Shorten the root ball
To get the azaleas bonsai deeper into the pot, some substrate or root ball can be removed. We have decided here to shorten the root ball.
The root ball is torn open with the root claw on the downside and the exposed roots shortened with an old bonsai scissor.
9. Fix the root ball
The azalea is realigned. Everything fits now. Hold the tree firmly and twist the fastening wire over the root ball. Cut off the overhanging ends with a wire cutter.
10. Incorporate soil
It is important that the bonsai substrate is thoroughly worked in between the roots. A thin stick (eg. chopsticks) is well suited for this.
11. Apply cover layer
Kanuma is a perfect substrate for azalea bonsai. It has only one small disadvantage - the color. Kanuma is light brown-yellowish, slightly darker when wet.
If you don't like this color you can cover Kanuma with a thin layer of other bonsai soil. Due to its dark grey color, expanded shale is quite suitable for this purpose. Best mixed with a slightly finer substrate such as soil for indoor bonsai.
12. Water root ball
Very important after repotting: Water the bonsai thoroughly. The best way is to dive your bonsai.
Attention: Kanuma is dry very light. Without being covered by another bonsai substrate, it floats away when diving.
4-6 weeks after repotting the fertilisation of the bonsai can start. Since the substrate is very acidic, bonsai fertilizers for azaleas should preferably be used.
Ready-potted Satsuki Azalea