Witches broom propagation?

[ACooke]

A bit of a throw-away question as i’m sure the answer will be ‘yes and it doesn’t work’.

But has anyone tried propagating the witches-brooms so commonly seen of she-oaks. What a nice, dense little ball of foliage that would be, to match the incredible bark so often present, should it be propagable.

I know with many other species, Acer immediately comes to mind, the abnormality found in some ‘witches-brooms’ will prove to be generic and carried over through cuttings/air-layers but i suspect this isn’t the case with the typical she-oak broom?

Thanks in advance!

[shibui]

Many of the dwarf conifers are from witches brooms too. Some need to be propagated by grafting when the species doesn't grow well as cuttings.
Have not even noticed witches brooms on sheoaks so not sure what might be the cause.
If the cause is genetic then it should continue in any plants cloned from the affected parts.
Definitely need to try some to find out.

[ACooke]

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Have not even noticed witches brooms on sheoaks so not sure what might be the cause.
If the cause is genetic then it should continue in any plants cloned from the affected parts.
Definitely need to try some to find out.

Oh really? I should have snapped some photos but they’re so prolific here i just presumed they were everywhere. I went for a walk today and without really looking out for them there’d honestly have been dozens i spotted - it seems like every second tree. I’ve also seen nursery material at bonsai world and bonsai south (potentially supplied by the former) with the same witches brooms on them and semi recall asking bonsai world what it was, to which he replied ‘a witches broom’ hahah.

I suspect both the above would have tried their hand at propagating it, alongside many many others) which is why i haven’t bothered bothered taking a cutting


If it turns out no one has tried taking a broom cutting (which i doubt) i’ll grab some photos and cuttings in the next week or few.

[Promethius]

Why not? I’m interested to see how you go. Share some photos when you can!

[shibui]

Maybe I just have not been looking?
Maybe it's something only found in NSW or northern areas?
Maybe it's some sort of bacterial or viral infection causing the abnormal growth? In which case it should still propagate as the cutting material would presumably also be infected.
Maybe it's not really a witches broom - though I expect most of our members would be able to tell the difference. There's a couple of mistletoes that use Casuarinas as hosts and might look a little like witches brooms at a casual glance.

A quick online search yields a few other articles so you are definitely not the only one to notice it.
I found one research paper that studied this but could only get the synopsis as the article is behind a paywall.

Abstract
Mycoplasma-like organisms were observed in the sieve elements and companion cells, and a rickettsia-like bacterium in the xylem cells of diseased plants. The MLO were spherical, oval or irregular, 45-300 nm diam. and with a trilaminar unit membrane c. 7.5 nm. The RLB were rod-shaped, 114-762 x 1000-1760 nm, with a well defined cell wall 22-28 nm. The MLO were also found in salivary glands of Hishimonus sp. and the RLB in Bythoscopus sp. Neither was found in healthy tissues.

I've found Allocasuarinas and Casuarinas difficult as cuttings but it can be done. C. glauca 'Cousin It' strikes reasonably well. There's also C. glauca 'Kattang Karpet' Maybe those were originally from witches broom infected plants?

[TimIAm]

Have a search at bonsainut forums. There is a lot of great info there, but it's spread across several threads.

From what I've read, the growth of witches brooms is a result of high cytokinin. High cytokinin to auxin ratio promotes shoot growth at the cost of root growth. If you are planning on propagation, you will have better chance grafting scions than airlayering or taking cuttings and getting them to root.

https://www.mprnews.org/story/2013/01/2 ... chs-brooms

Would be an interesting experiment to see if you can have success. Keep us posted if you decide to have a go.

[Rory]

Yes, Casuarina gets witches broom.
Do not propogate it. It’s sickly growth that will die in hard times.
People have propagated it before yes, but it will eventually die. It’s not healthy, and any witches broom I’ve had eventually always dies back or dies in drought conditions or even just naturally.

People have propagated them much to my warning, and they eventually died too.

There is no point. Casurina glauca ‘cousin in’ is a fabulous dwarf variety of glauca that is very healthy and simply has short internodes.

If you want smaller fine needles, try Daintree Pine.
It’s in the Casuarinacea family, and is lovely and has short needles. Very pretty too.

[ACooke]

Yes, Casuarina gets witches broom.
Do not propogate it. It’s sickly growth that will die in hard times.
People have propagated it before yes, but it will eventually die. It’s not healthy, and any witches broom I’ve had eventually always dies back or dies in drought conditions or even just naturally.

People have propagated them much to my warning, and they eventually died too.

There is no point. Casurina glauca ‘cousin in’ is a fabulous dwarf variety of glauca that is very healthy and simply has short internodes.

If you want smaller fine needles, try Daintree Pine.
It’s in the Casuarinacea family, and is lovely and has short needles. Very pretty too.

Thanks Rory; that’s very helpful and much what i thought was probably the case. I’m not overly concerned about finding a denser/smaller internode variety but if it’s right in-front of you at every turn - it’s difficult not to question, if only out of curiosity haha.

I’ve got a little torulosa I’ve been messing about with; and i quite like the foliage. Very purple and the new growth gives this illusion of almost a vibrant orange hue between the older purple foliage and new green tips. Whilst certainly whispy, it’s very cool. It’s new enough that i’m not yet certain if that’s normal or a seasonal/post repotting abnormality. Either-way, it’s very interesting.

Thanks again.

[Promethius]

If the phenomenon is truly localised to ACooke's local region, it may be due to either a local population of trees with a shared genetic vulnerability to witch's broom, or (more likely, I imagine) an insect population that's carrying the trigger for the abnormality.

I'd initially assumed all WB to be a mutation, but a bit of reading (behind the paywall, thanks to an anonymous institution) suggests that most WB are due to infections - viral, fungal, intracellular bacteria etc - delivered via insect vectors. The infection affects function at a point in a branch, leading to alteration in gene expression locally. A tumour forms at the site of infection, and the broom develops downstream along the branch, resulting from local changes to gene expression. The broom itself acts as a way for the pathogen to keep reproducing and spreading.

Based on this, I think Shibui is right: the broom will contain the pathogen and therefore quite possibly the trigger for the abnormal growth pattern. The results will probably be unpredictable for bonsai, and I wouldn't want to keep other casuarinas nearby in case it spreads to them, but you don't know til you try.

[ACooke]

I don’t think it’s localized to my region although i guess that’s how you define local. I’ve seen if very commonly locally to where i live, as in within a half an hr’s drive - where i commonly walk, as well as a few hr’s further North around the central coast region - i presume it’s also much further spread.

I’m also sure i’ve seen it on Torulosa (which i don’t think is overly common to my locality - Royal National Park/Heathcote NP) as well as what i guess are Littoralis or cunninghamiana maybe? i’m not sure what the local varietals are tbh.

I’ll grab a few photos next time i go for a walk.

[ACooke]

Alright, so I swung by the local oval and grabbed some poor-quality photos, quickly.
This is what I'm referring to and is identical and super-common in both our national parks and council land etc. It also, as far as my very botanically-novice eyes can tell, spans more than one variety of Allo/Cassuarina species (but take that bit with a grain of salt).

I'm sure this is what Rory is referring to.