AusBonsai

The banksias occasionally self seed in our garden. This year I was told to remove a couple that were getting a little too big for the area they were growing in.

In the past I've successfully transplanted these from October through to January. They don't even seem to mind being transplanted in quite hot weather. Daytime max temps have been in the mid-high 30sC this week. Attempts to transplant banksias in autumn and winter have been unsuccessful.

A couple of years ago I trialed a number of different timings - dig and cut in one operation; cut a few weeks before then dig when new shoots start growing; dig without pruning. All of these gave similar survival and growth rates.
At 2 m tall these were a little too big to dig without pruning so, as you can see, I cut them back a few weeks ago in preparation for transplant.
It took a bit of work with shovel and crowbar to get this one out on the ground but fortunately banksia roots are relatively brittle so I don't need to dig right under the trunk, just dig down the sides and wobble it until remaining vertical roots snap. I don't try to keep the soil intact when I transplant trees. When I dig I generally shake and poke the rootball to dislodge as much garden soil as will fall away easily.
Next comes root pruning. I know a few of you will be horrified at how much I've reduced these roots. This is, in fact, the hardest I've ever reduced banksia roots when transplanting. The trunk is not particularly attractive so I decided to use this one as a test subject. After initial root pruning the root ball was just a little larger than a 30 cm orchid pot so I either needed to find a larger pot or reduce the roots just a bit more..... Apologies for the orientation. Ausbonsai upload appears to rotate pics back to the original orientation.

If you can tear your eyes away from the butchered roots you can see the new shoots resulting from the hard prune a few weeks ago. Banksias respond really well to hard pruning and produce lots of new buds, even on older, bare wood so don't be frightened to cut banksias. Note those shoots are all clustered near the ends of remaining trunk and branches. Probably would have been better to cut this trunk a little lower. There's not a lot of room but I did get some mix around those remaining roots. Because it is still pretty tall I had to tie it into the pot so it won't fall over.

Watered in well then into the recovery spot - under a bench this year. Still plenty of light but out of direct sun for most of the day. They'll get watered with the rest of the trees twice each day -early morning and evening.

That's the 3rd transplant so far and there's still a couple to go.
and see how they go.

That a nice size banksia shibui. How big are the others you have to dig as well. Keen to hear how they all go.

Nice work. These look to be B. Integrifolia to me shibui, is that correct?
What are your thoughts on doing similar work on other banksia species?
Same, same ... or different!

This was the thickest and tallest of all the banksias I have to dig this year. It might be fat but not much taper or shape IMHO. The others are a little thinner but not much. I dug the smallest one today trunk around 5cm? thick. Fortunately the others have much better taper and shape in the lower trunk than the one I showed here.

I'm not too certain what species these are. There are quite a few integrifolias in the garden and they do self seed so it is possible the seed has come from integ but this area has other species and I've lost track of the names if I ever knew them.

I have done similar with B. serrata with no problem. From repotting B. marginata I'd guess they should also cope well. Both tolerate radical root reduction and sprout profusely all over the stump when pruned hard. I haven't tried other Eastern species enough to give informed opinion.
Western banksias don't like our cool, wet climate here and they don't live long enough to get to know them.

These last few threads have been awesome. Thanks for giving so much information to a public forum

Just an update on this banksia.
A check of the weather records shows we had a few days of cooler weather in the days after transplant with daytime temps around 30C. The following week saw temps rise into the 40s and high 30s.

This banksia and most of its colleagues are still looking healthy. A few of those new shoots have died off but most continue to grow.
A couple of the others dug around the same time: Apologies for the orientation. Despite having turned these pics in my files Ausbonsai seems to like to revert to the original format when adding files. you'll just have to turn your heads or lie down to look

I love your root pruning. My eyebrows practically rose off the top of my head the first time I saw how much you root prune your tridents.

More like ‘remove all roots’ rather than root prune, but helps produce really good basal flare.


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Really radical root reduction like this will kill some species. If you are unsure leaving more roots and reducing them over time is a safer strategy but I'm exploring possibilities to find species which can tolerate this sort of treatment because it may actually shorten the time from collection to bonsai.

Good to see the trees survived. Banksias are very hardy as I'm finding out. If I need more branches further down I just chop the top harder. Cheers for the update

Hi Neil,
Did these survive? Would you do anything different now?

Cheers,
Symon

50% survival for this batch which is my worst ever result. The tall one shot plenty of new shoots but gradually deteriorated over the next 10 months until I had to admit it was not going to survive. The autopsy revealed no new roots which is something I have seen occasionally in other species too.
As for would I do anything different? Maybe keeping a few more roots would have helped? I can't think of anything related to aftercare. This one was treated the same as all others. Past experience points toward more humidity NOT being conducive for banksias. Looking back at the photos maybe more sun could have made a difference? I've noticed in past attempts that lack of sun appears to have a negative affect on survival after transplant.

Occasionally it just comes down to the health and vitality of the individual tree. These were from a remote garden bed halfway down the drive so they have relied only on natural rainfall with no additional nutrients. The outcome may have been different if the trees were watered and fed a bit in the year or months before digging.

The truth is that we just do not have enough collective experience with native species yet. We are only just gathering enough data to start to generalize so the more people who contribute survival and death experiences the sooner we'll be able to offer real suggestions.

Thanks for the reply. I was shocked that you could treat banksias like this. I have some 'weedy' banksias myself that I will now have shot at. Thanks again for the post!

I have had mixed results with natives and it is frustrating. Whenever I think I know how do a species and get over confident I get a kick in the pants. These posts with follow ups are very useful.

Cheers,
Symon

I agree Symon. Just when you think you know what you are doing the next one will be perverse and react differently.

Good luck with your transplants.

shibui wrote: ↑September 30th, 2021, 10:34 am I've noticed in past attempts that lack of sun appears to have a negative affect on survival after transplant.

I wholeheartedly concur.
Any Banksia I have heavily root pruned and reported, will deteriorate quickly if it is not given a lot of sun.
Banksia in particular love a lot of sun, but from my experience B. integrifolia is one of the most tolerant of low sun.

However with nearly all my natives, after a heavy root prune, if they don’t have a lot of sun, it can badly affect them and they begin to deteriorate quickly.

A lot of people seem focused on allowing their natives to recover in shade or dappled sun, but the best recovery is the same strong sun it was in beforehand, from my experience.

Casuarina is one of the few trees that doesn’t seem bothered at all if it’s not in decent sun after a heavy root removal.

But trees like Melalueca, Banksia, Baeckea, Eucalyptus, and a lot of Leptos can start to suffer if they don’t get decent sun after a heavy root reduction. And also especially for younger material. There must be a higher need for the tree to use the suns energy to grow roots and recover??

Although I now leave considerably more foliage on all my natives after a root removal then I used to.

Rory wrote: ↑September 30th, 2021, 8:57 pm Although I now leave considerably more foliage on all my natives after a root removal then I used to.

There is good science to support this. I'm sure sugar production is a big part of it, and the other is the auxins present in the terminal growth that supports root growth and suppresses new shoots. If you cut back hard the tree favours new shoot growth over roots. Species dependant of course.

Large landscape trees used to be cut back routinely on planting out, until it was shown they transplant far better when left with plenty of foliage. Again, species dependant.