Banksia integrifolia 'sentinel' 1

[Rory]

Progression thread : Banksia integrifolia 'sentinel' 1

With all dwarf Banksia varities:

- I use ~50% washed coarse river sand
- Don't use any sort of liquid fertilizer on these, even in low strengths. Only use slow-release native pellets.
And for me, I only apply fertilizer about a month or so after the material has been root pruned, just to be safe.

Only repot at the start of the strong growing season, NEVER towards the end of the growing season.

Since changing to this method, I have not lost any Banksia dwarf varities and I'm quite excited about growing them.
They have the same attributes as the parent ; they're incredibly hardy and I've found them just as tolerant of drought as the main species.

The leaves are naturally shorter, but they can get a little fat.
The leaves also reduce well, and the tree usually shoots anywhere from a cut.

I found that with Banksia you can remove a huge percentage of the roots and still leave most of the foliage on and not worry about any die-back.
They're the hardiest tree I've ever worked with in regards to root removal.

I've since changed my mind on Dwarf Banksias. I now recommend dwarf Banksia varieties for Bonsai, as I've managed to keep all the new trials alive.
I found the difference is mainly how you apply the fertilizer, the drainage, and the time of year you do the rootwork.

When I'd previously used liquid fertilizer on dwarf banksia, they'd usually die soon afterwards. Now this was even after removing any proteoid roots.
So I only use slow release fertilizer pellets, such as Osmocote.
Don't keep dwarf Banksia varieties in heavy mixes ; keep them in a fast-draining, open mix with plenty of washed river sand.

Don't remove a lot of the foliage on Banksias.
With the first root prune, you can go hard on the roots of Banksia, but leave at least 60-70% of foliage on the tree to fasten the recovery - sometimes I don't even cut any foliage off!

Only cut back roots on a banksia when nights are over about 10 degrees, and don't do it at the end of summer or in autumn.
It needs time to push out a lot of new growth and even more time for the leaves to harden before winter.
It needs time to regain health before coming into winter and you want to have the roots constantly pulling water out of the mix, not sitting in a wet mix over winter.

Now having said that, if the roots are staying wet too long and drainage becomes an issue, then repot immediately.
Separate the roots (cut off any that are rotten), bare-root and remove all the old soil and replace it with a fresh mix, adding in washed river sand.
I've lost more Banksia from root rot, than from drying out. With a few exceptions I've trialled, most Banksia can tolerate drought really well.

So I recommend repotting in mid Spring or late Spring, or even at the start of summer. But if you're in a colder climate, that might be later in the year.

The hardiest and easiest to grow for beginners would probably be:
Banksia integrifolia and Banksia spinulosa.

B. integ 'sentinel' 1-01 22Dec2019.jpg

22Dec2019

B. integ 'sentinel' 1-02 19Apr2020.jpg

19Apr2020

B. integ 'sentinel' 1-03 15Jan2021.jpg

15Jan2021

[Rory]

I had a borer on this one.
You can see all the cambium that was munched on it. I killed the bug, but it had eaten a fair bit, and almost ring barked it. It ate halfway around the trunk.
The goal now is to allow it to grow like crazy and encourage the base to heal quicker.

The lesson here is to keep your collection to 50 trees or less. Otherwise you aren't providing proper care.

B. integ 'sentinel' 1-04 10Jan2022.jpg

10 Jan 2022

[Keels]

The lesson here is to keep your collection to 50 trees or less. Otherwise you aren't providing proper care.

I feel your pain. Too many trees to manage you'll always have a few that suffer.

Would that scar even heal over? You'd have to get the tree to double in size to cover that section?

[Rory]

Would that scar even heal over? You'd have to get the tree to double in size to cover that section?

My plan was always to have a much bigger tree yes, so it shouldn't be a problem. The base grows incredibly fast.
Time will tell.