AusBonsai

Hi all,

On the 28th of January I repotted a Banksia marginata, a Leptospermum laevigatum and a Eucalyptus vernicosa ( a dwarf Tasmanian alpine Eucalyptus).

The Lepto had about 80% of the roots removed and moved into a smaller pot. The Eucalyptus had a small root trim and tease out of roots into a larger pot.

The Banksia squeezed into a pot of about the same size but lost a good 30 or 40% of roots.

ATTENTION. NO Foliage was removed from any of the trees. The Lepto was in lots of hardened off but new growth; same with the Banksia, the eucalypt had also had a small amount of new growth(Not Soft)

The temp was about 32degrees, the next day 34, then 38, 38 , 35 then 20. They all survived and thrived, the colour on the eucalyptus especially darkened in colour.
The Lepto and Banksia have since been trimmed , the eucalyptus was left as is.

Just saying. I like summer repotting of natives.

Grant Bowie

I also repot most of my natives in December and January with similar results. Even trees with lots of growing shoots seem to thrive after root pruning in summer.
Last summer a number of mine experienced daytime temps over 40C in the week after repotting and still no sign of distress.

Yep, awesome post Grant.
When I first started growing Bonsai, everyone used to tell me to reduce most of the foliage or at least to equal out the same reduction in foliage as root.
I have found that logic to be outdated. I do the same as Grant now. I have not had any problems with my natives by leaving foliage on the tree. Banksia and Casuarina and Lepto in particular I find will benefit from having more foliage left to aid the recovery. Perhaps foliage reduction from root removal is a northern hemisphere trait that works better for exotics maybe?

Also high temps have never bothered any material when I’ve reported them either. Excellent thread Grant

I repotted 2 banksia and one Eucalyptus about 10 days ago. They were looking a little sad and I noticed they had become pot bound. I went light on the roots ( probably removed about 20%) because I usually repot them in October and I just wanted to see them through. In the last 10 days I have noticed a marked improvement in their health.
Mid December I repotted a Eucalyptus nicholii (this one) and it died almost immediately!
I had grown it from tube stock.

Nicholli seem very strong when it comes to cutting back for ramification, but maybe not roots? Did you trim foliage?

Grant

That’s odd. I’ve found E. Nichollii to be very hardy.
It’s slightly affected by myrtle rust, but otherwise for me they are a very hardy tree and tolerate a fairly decent root reduction.
That is a real shame.

I usually do rootwork in about October/November with Eucs though, they just seem to respond better for me.
I can often get dieback with Eucs after a root prune though, so I usually don’t touch the foliage much at all and let the tree work itself out. This has proven to work for me so far.

By the way Grant, that Euc is lovely. There’s something about that I really love.

And to the Banksia marginata lovers.... take special note of how bushy Grants marginata is. That’s the only thing that works for me with Banksia marginata. Keep the foliage bushy and lightly trim it stage by stage.... never in a big reduction.

Yeah it is a real shame Rory. I cut it back moderately hard at the end of winter and it powered into spring, it needed repotting so I waited until December instead of October which is my usual time for natives. It had suffered some major unexplained die-backs over the last year or so which is why the timing was all off. I grew it from tube stock and over the previous 10+ years I never had any such problems - it was a hardy tree.

After repotting in October my natives' roots almost always fill the pots to the point of action by late January/early Feb., and they seem to love a minor root prune/teasing/slip-potting at this time of year - at least for the last 5 or so years that I've been doing it.

I have been following the same methods, spring is very busy with repotting exotics while many of the natives seem to be slightly dormant. Growth is rampant on the natives in November, December and January when newly potted trees seem to recover and fill pots with new roots very quickly with most natives potted every year, BUT........... we need to understand and experiment with different species. I have had an elaeocarpus (blueberry ash) which has been weak for many years and never seems to fill the pot with roots, this year I have not repotted it, I removed the flowers to avoid fruiting and tip pruned. The tree is much stronger than ever before and perhaps will be better suited to a springtime repot?

I note that the eucalyptus mentioned was cut back hard at end of winter. I NEVER do this. I wait till it is warm to hot before cutting or trimming foliage on Eucs. maybe that is what set it back and then the repot finished it off. Two insults too close together.

Grant

Grant Bowie wrote: ↑March 11th, 2021, 2:18 pm I note that the eucalyptus mentioned was cut back hard at end of winter. I NEVER do this. I wait till it is warm to hot before cutting or trimming foliage on Eucs. maybe that is what set it back and then the repot finished it off. Two insults too close together.

Grant

Yeah I would agree with Grant. The only time I’ve ever repotted Eucs in winter or around winter was because of drainage issues or other reasons beyond my control, but it’s nearly always dangerous. Dieback or death can often eventuate. But there are certainly Eucs that are more susceptible to winter dieback than others. I get what Gerard is saying. Some Eucs would die back at the mere sight of pruning in winter and others wouldn’t fair too badly, but on the whole it’s not something I’d experiment with on aged material.