Banksia Integrifolia

[Albo]

Hi all,

My name is Alan, I’m getting back into bonsai after many years away. I reside in Sydney near Parramatta.

Was hoping to grab some advice if possible as I have next to no experience with Banksia.
I recently picked up this Banksia Integrifolia from flower power. It was about 5 foot tall with a dead straight leader that has been great for thickening trunk. I’ve Removed the leader and slip potted into a flower pot the next size up as it was pot bound with roots growing out the bottom. No root work done apart from cutting the roots growing out of the pot.

After reading some of the articles that have been posted on this forum I realise that maybe I should have removed some roots as I know it has those fine proteoid roots. I saw them when I repotted. Didn’t know what they were at the time.

I potted it about three weeks ago. It does look to be pushing new buds in places.

Probably my main question is should I remove it from the pot and remove some roots or just let it be?

It’s in Ray Nesci standard bonsai soil and I’ve put a little bit of standard Ozmocote.
I’ve attached photos, hopefully they go through ok.

Any advice would be appreciated.

[Phil Rabl]

Grant Bowie is the B. integrifolia guru. His landmark Ausbonsai post has been viewed over 91,000 times. Here is a link to that post. viewtopic.php?f=69&t=812.

Grant’s tread is pretty long now, so you might find it useful to read the summary of Ausbonsai posts on B integrifolia that I did in 2019. It draws heavily on Grant’s work. It also updates some of Grant’s thinking (I spoke to Grant before posting the summary). Here is a link to my summary.
viewtopic.php?f=69&t=27698

Good luck with it.

If it were my tree. I would remove the proteoid root.

[Albo]

Thanks Phil,

Its extremely helpful all the information you guys on this forum have been compiling about these iconic natives.
I will be studying your summary and Grants thread.

I’m leaning towards removing the proteoid roots. It seems there is only upside to removing them and potentially risky leaving them.

I appreciate the direction and advice.

[Phil Rabl]

A banksia with proteoid roots can take up phosphorus at toxic levels. That's the risk, and the main reason for removing them. A well fed banksia won't grow proteoid roots. So, the general advice from Grant and others in the know is to remove the proteoid roots (at the appropriate time) then feed the tree on half strength normal fertiliser for a couple of months, then move it to your normal fertilising regime. You don't need to use fertilisers marketed for Australian natives. In fact, most Australian natives don't grow proteoid roots and should be fertilised with normal fertiliser all of the time.

[Albo]

Thanks Phil,

I actually picked up 2 on the same day. They were both on the clearance rack for $2.70 if you can believe it. I thought I’ve got nothing to lose.
The nursery has done a couple years of growing for me Id say?

The other is in the same boat, was about 4-5feet tall, I slip potted into larger flower pot and selected a new leader for taper.

Do you think I should remove the proteoid roots now or wait until the end of summer? It seems to be a very mild summer here in Sydney. Weather forecast for the next couple of weeks is showing no more than 30°

[Phil Rabl]

I would remove the proteoid roots now. Fertilising a banksia with proteoid roots can kill it. This is the right time of the year to do a root prune but if a major root prune is not needed, just get rid of the proteoid roots and hold a major prune off until next summer, as the trees come into growth. That may be November in Sydney - but check with locals about timing. Once you get your trees used to fertiliser they won't (shouldn't) grow any more proteoid roots.

[Albo]

Repotted both and I’m glad I did.

The shorter fatter one was packed with proteoid roots. By the time I got rid of them I’d gone through about 40% of the root mass. Actually dropped it back into its original pot as the Orchid pot was too big now.

The thinner taller one was much better. Only removed about 20% of roots and back into the orchid pot.

I believe the course of action now is to keep them in the shade for a while and start fertilising lightly. Bring into full sun in a week or two?

Hopefully they both survive but I realise these are issues I get when you buy cheap nursery stock. But they were so cheap is worth the experiment.

Will do updates on progress.
Thanks again for the advice Phil.

[Rory]

So you say you bought them 3 weeks ago, and slip potted, and heavily trunk chopped. Then 3 weeks later, you've now taken them out and removed all the proteoid roots.

So I would not have done this. Banksia develop proteoid roots yes, but from my experience the main time this is a problem, is if you use liquid fertilizer on them. Thats when I've had problems. Banksia are incredibly good at getting nutrients from poor soil. They can go for a long time without fertilizer and if you had used a fresh mix, you didn't have to be concerned about fertilizer for ages. I would have left them, because now the tree has just recovered from the severe trunk chop and adjusted to its new home, and it was busy pushing out new shoots after the shock.

Going forward, if it was me, you obviously remove the proteoid roots at root prunning.... but with any material for bonsai, we don't normally slip-pot, especially if its the strong growing season. Just separate the roots next time at the first root inspection, and remove proteoid roots. Banksia integrifolia is incredibly hardy with root removal, but doing so after just 3 weeks after a trunk chop and after its started its new flush, is not an ideal time. The danger is that it just sulks after putting out the first flush and that the first flush may die off and still sulk.

Put Banksia integrifolia straight into full sun after a repot or root removal. I would not put them in part shade. You need to introduce the new shoots to full sun. They love it. But again, if its been in low sun, and you move to full sun, you may get burn, but not on the new growth that shoots.

Take care and good luck.

[shibui]

I've had good success transplanting banksia integ (with major root reduction) a few weeks after doing a major cut back. The trunks were just opening new shoots at transplant time. I don't think this transplant will cause any problems.
Similar success rates when the trees were pruned hard at the same time as transplant.

For me down here in cooler climate, late spring and summer are the better times of year to do root reduction on banksia. Too late in autumn and they don't seem to recover then sulk for nearly a year before taking off again.

40% proteoid roots seems like a lot. Banksias also have lots of fine roots that are not proteoid so just check that you really know what proteoid roots look like.

[Albo]

Thanks everyone for the input,

I’ve learned heaps just from this exchange.

The roots I refer to a proteoid are like sponge, some white some brown. I should have taken photos.
I have seen the photos you have put up as examples Shibui.

Are the brown ones also proteoid or is it only the white?

Hopefully I haven’t gone too far and become a banksia murder.
Time will tell I guess.
I’ll keep you posted.

[shibui]

I'm pretty sure only the white 'starburst' root formations are proteoid roots. Fine brown roots are just ordinary feeder roots or possibly dead proteoid roots if they have that distinctive starburst formation.
My experience is B. integrifiolia cope well with root pruning, even severe root pruning provided they are active and can recover quick hence the spring/summer timing for me.
I've removed up to 80% of roots of young trees and over 50% on bigger trees. Occasionally one dies for unknown reasons but most just keep growing.

[Albo]

Hi All,

Only been a few days but seems fine. No buds have died off yet. I’ve placed back in full sun.
Being positive and this survives, what would next steps be in regards to pruning?
I’m assuming I’d just let it grow and get stronger until next spring but not sure

Also should I start liquid Fertilising now? I’ve just put a bit of standard Ozmocote on atm.
Should I start using power feed considering it’s only been reported with some root reduction a few days ago?

If yes for power feed, should I do say 30 ml per 9L can?

Any advice or suggestions appreciated.

[Rory]

It’ll survive for sure. Integrifolia is very hardy.
But I would let it sit and recover at least until next Sunmer.

I don’t Use liquid fertilizer on any of my Banksia but most members here do. Osmocote slow release pellets is plenty for them, but each to their own.

Have fun.

[Albo]

Thanks Rory,

I’ll just enjoy watching it grow till next year.
Appreciate the advice.

[Phil Rabl]

In December 2022, I repotted a Banksia marginal that I had purchased based from a nursery a year or so earlier. I had never seen the roots before the repotting. I was a little surprised to see it had proteoid roots. The proteoid roots are the flat roundish clusters of roots mainly in the centre of the photo below. I cut them off during the repotting and am now feeding the tree with normal full strength fertiliser - liquid and slow release. It is powering away.

There is loads of information on proteoid roots on the internet. Some of it's very technical.