Candle reduction and root prune in one season - too much stress?

[AndrewBigwood]

Hi Bonsai people, I finally decided to join, and here's my first post:

3 years ago I started to transition one of my Scots pines from organic to inorganic substrate.


I followed a tip from an expert, stating that to minimise the tree's stress, only remove organic matter from one side of the tree root system. I did that, the tree recovered and I now have a very healthy, thriving tree with good long candles.


My dilemma is whether I should remove the organic soil from the other side of the root system in August/September, as well as prune/reduce the new candle growth to prompt back-budding in late May(2 weeks)?


Will this be too much stress for the tree, or will the tree have recovered from the candle pruning/reduction by August/September?


I'm keen to get the tre einto inorganic substrate to minimise the wet roots that organic soils create over the UK south's autumn/winter seasons.


I should add that the current soil, although organic on side, does drain well. The tree is also in a pond basket.
Any advice appreciated.

 

[Wires_Guy_wires]

Show us pictures of that strong growth and we might be able to judge.

I don't know about your climate, but it's similar to mine. And I cut my shoots for backbudding when the needles have hardened off, like described in the scots pine care sheet v2 in the resources page.
Doing it too soon might trigger a second flush and that will weaken your plant.

 

[AndrewBigwood]

"Show us pictures of that strong growth and we might be able to judge."
Apologies for the lack of pics when posting.

Thank also for mentioning the care sheet, I'll take a look at that.

 

[roberthu]

If you repot and reduce foliage in the same year on a short needle single flush pine, you will likely get some back budding but later lose almost all of it, end up killing the tree. I’d let the tree alone to let it rebuild the roots and prune back next year or even in 2027.

 

[AndrewBigwood]

Thanks Roberthu, I'm in no hurry and the roots can wait.
I'd like to address the tree's branches if possible.
Due to unforeseen circumstances, I was unable to prune last year's growth, and now I also have this year's growth to contend with.
The branches are becoming too leggy, and I'm hoping to address this issue with back budding, via pruning some or all of this year's growth, or even pruning into last year's needle growth.
Are either of these feasible plans?

 

[Paradox]

I would do the other half of the roots at the proper time.. ie spring as buds swell

 

[bwaynef]

Your mention of August/September as it pertains to repotting makes me need to know: where are you located?

 

[AndrewBigwood]

Your mention of August/September as it pertains to repotting makes me need to know: where are you located?

I'm in the South East UK.
Until I returned to bonsai in 2021, I was also under the impression that repotting should only be done at visual bud-swell (or equivalent) in the Spring.
Since I joined the Bonsai UK Facebook group, I noticed that there were quite a few seasoned bonsai people repotting in the August/September/October period.
This repotting time is also verified by @Wires_Guys_wires, in the Scots Pine Care Sheet V2.

This year will be my first season using the 'Fall' repot time.
I have 2 JBP 4 year olds that I'm using to see how the repotting times affect their yearly development.
I repotted one JBP in the Spring, with a view to repotting the other in the fall.
The one I've already repotted has developed less in terms of candle length that the one that's not repotted yet.
The repot also involved transitioning from organic to inorganic.
I'm interested to see how the JBP I repot in the Fall, recovers and develops next year.

I had assumed that the Fall repot period was more widely known, or am I overlooking something?

 

[roberthu]

Thanks Roberthu, I'm in no hurry and the roots can wait.
I'd like to address the tree's branches if possible.
Due to unforeseen circumstances, I was unable to prune last year's growth, and now I also have this year's growth to contend with.
The branches are becoming too leggy, and I'm hoping to address this issue with back budding, via pruning some or all of this year's growth, or even pruning into last year's needle growth.
Are either of these feasible plans?

I wouldn’t worry about long branches yet. Pines back bud on young branches until they are 5 or so years old. You can wire them down but keep the tips pointing up to redirect auxin flow to promote back budding without pruning. I’d focus on the roots first and repot next spring to replace the soil on the other half. Then really get working on the branching in 2027.
A healthy root system is the foundation of a healthy tree.