Natives - does defoliation work?

[JimmyBanks]

Evening all.

So I’m interested in finding out from people who’ve got experience with natives and was wondering if defoliation has been successful with eucalypts and other Native in order to make smaller leaves and get better ramification.

I have a couple of flowering gums, a couple of manna gums, as well as red river gums and was contemplating getting some mountain ash. I’m just concerned that the leaves will remain large.

[Bougy Fan]

Natives cover a lot of different species. There are some that will not back bud on old wood, so if you defoliate you may lose them.

[EdwardH]

Hi Jimmy
In my experience, most euc's leaves will reduce in size with defoliation. Whether they get down to a size that you are happy with is another matter. My e. melliodora has just shot new leaves after a pretty hard prune and are 15-20 mm long, about 1/3 the original size. I'm still developing the branches so leaf size is not my main concern but it is pleasing to see the foliage reduction. Reducing internode length is again another matter and will probably be your biggest issue to overcome. Some species will reduce quite nicely whilst others just don't want to play ball. You have to experiment with the varieties to see how they respond.
Cheers

[LLK]

Edward, there seems to be a confusion between defoliating and pruning. Did you systematically remove all the leaves, as one does with maples, or did you prune, i.e. shorten, or remove twigs?
Anyway, congrats on the result.
Some before/after photos would be nice!

Lisa

[GavinG]

I can remember two posts about defoliating Eucs - PeterH defoliated a E. polyanthemos, and the new leaves grew back larger! And Rory recently posted about defoliating E. punctata - not much joy the first time, but when he repeated it shortly after the leaves were smaller. He might chime in. With constant pinching most Euc leaves will reduce, but only so far.

It might be an interesting technique to try on the larger-leaved Mels and Calls like M. quinquinervia, but I can't remember anyone doing it.

No need to defoliate on the small-leafed natives (Leptos, Beackeas and the like).

Acacias won't reshoot on bare wood generally, so I don't like your chances there.

I don't know how the rainforest species like Tristaniopsis would go, but it might be worth a try on a tree that's not precious...

For my money, (and particularly for Eucs) if the leaves are large and the internodal distances are long, it might not be the best species to work with. E. crenulata, E. dalrympleana, E. parvifolia, E. cinerea, E. bridgesiana, even E. scoparia all have more or less small leaves and short internodes. They're probably more cool-climate Eucs- what's available in Sydney and Brisbane I'm not sure.

Hope this is helpful.

Gavin

[Rory]

From my experience you can greatly increase the duration of success from consecutive defoliations, but eventually the species' leaves that I've trialled continue growing bigger in time, albiet slowly. Tip pinching and constant pruning can assist in maintaining the reduction, but sometimes it can cause die back on some species, or affect the health of the tree from my experience.

I prefer to start with smaller leaf varieties, otherwise I grow the eucs big. I've seen so many beautiful pictures of large leaf Eucs with small leaves..... but give it a few more months and usually the tree doesn't look as good as the leaves continue to grow. For this reason I don't usually bother with large leaf varieties because anyone can display them after 3 or 4 weeks from a defoliation for a show and give a small leaf representation, but I want something that looks in proportion for most of the time at home for me.

Good luck with it all. Just remember.... In my opinion if the Euc isn't in 100% health, don't do a complete defoliation. By memory I don't think I completely defoliated all the leaves, just 80-90% which is the same effect as total defoliation, but I found it seems to reduce any die back occurring.

[Gerard]

I like to defoliate all the largest leaves and fine new growth at tips on eucs and banksias. If the tree is not so strong I cut larger leaves in half in an attempt to force new budding

[JimmyBanks]

Thanks everyone for your responses. Really appreciate it. I will definitely give it a go and see what the results are.

[Starfox]

Good question and funnily enough I was thinking about this last night as there was a Koala documentary on with a segment about whole swathes of forest that had died off because of the constant defoliation from the Koalas as instead of recovering via photosynthesis from the leaves they have to keep drawing energy from the roots until it is depleted. That made me think that if one was to defoliate a Euc then maybe it is best to do so partially or wait a significant amount of time in between defoliations to restore the trees energy before doing it again.
Then again maybe it is species dependent as some will back bud, refoliate and backbud quite easily whereas others simply don't.

Either way it's interesting.
What about defoliating juvenile leaves? Probably best not to?

[GavinG]

I saw Grant defoliate a large old Banksia yesterday, he seemed confident.

Starfox, because we prune so hard and often, we're usually dealing with juvenile leaves. Probably best anyway to pick species with small leaves.

Gavin