Eucalyptus tereticornis Bonsai Trail

[Kevin]

Hello all,

In relation to my earlier question: Will E. tereticornis make a viable bonsai specimen? viewtopic.php?f=78&t=21339

I began collecting seeds from my local indigenous E. tereticornis trees which just did not want to germinate. Fortunately on my 4th collection of seeds, collected on 17 March 2016 and sown on 19 March 2016, 2 seedlings germinated exactly 1 month later. Unfortunately, last week when applying a tad of Dynamic Lifter for turf 1 became deceased.

Below is the seedling on 20 April 2016:

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Below is how the plant looked this morning. I have been extremely keen to advance the plant to a larger container but unsure if i should wait for warmer weather - Spring. My worries are it keeps growing throughout temperatures from about 0 - 10 degrees (overnight).

As i have never personally grown any Eucalyptus plants previously, I would appreciate some advice as to what i should and shouldn't be presently doing. The plant presently stands at 230mm and is about 10 weeks of age.

All help welcome please.

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Thanks in advance,
Kevin

[shibui]

I have not been particularly successful with Eucs as bonsai but I can help with growing them generally.
many natives are developed by 'slip potting' just remove the entire root ball intact (as intact as possible but losing some mix does not usually cause problems) from the existing pot and place it into a new, larger pot then top up with required amount of mix. Because it does not involve cutting roots you can slip pot any plant any time of year. A larger pot will usually result in increased rate of growth and development.
It looks like you have the tree in a container with holes (colander)? If that's the case you can supply extra root run just by placing the colander inside a larger container and adding extra mix. the roots can penetrate through the holes to access more space and nutrient but cannot grow too large so removal is easier in following years.

I am surprised at the lack of success with germinating see. They usually come up in thousands. maybe we need to work on identifying ripe seed capsules and seed germination technique?
Also surprised that one has died as a result of fertilising. Eucs normally enjoy fertiliser. Could some other factor have caused the expiry?

[Kevin]

Thanks Shibui,

I thought the repot with minimal to no root disturbance would be okay, just ensuring as such practically does not go as always planned. I'll just need to be extra careful. What i would like to prevent from occurring is the development of a significant tap root, so a larger flat colander will be attempted probably tomorrow as we have steady rain forecast for several days and from experience you cannot get a better opportunity than natural rainfall for all round plant performances.

As for germination, or lack of, i contributed this to old seed. As you can image an indigenous specimen of some 30+ metres in height i was scrambling around the refuse beneath the tree for capsules. Which meant that as the tree flowers in spring, the capsules were more than likely old and / or diseased. Luckily i have one now to play with. I have kept an eye on several nurseries unfortunately they do not stock to many eucalyptus around my area, anyway i would much prefer fresh seed from a local indigenous specimen and await spring / summer for fresher seeds now.

As for the deceased seedling, it was the far weaker of the two and i believed the stronger concentration of the Turf variety directly upon the foliage responsible for its departure.

Thanks again for your assistance.

Kevin

[shibui]

Collecting fallen seed capsules explains a lot. Normally when the seed is ripe the capsules open on the tree and drop the seed. Much later the spent capsules fall but by then they are almost always empty. In my experience any seed that is left after initial seed drop is very unlikely to be viable. I have found this with many species including exotics like pine.
To get good seed you need to target unopened seed pods but I understand the problems with very tall trees. Best opportunity to collect is when the wind has picked a branch or 2 for you and dropped it on the ground. Also sometimes after the cockies have been there will be small branches of ripe pods on the ground. You need to be quick though. Seed capsules open and spill the seed as they dry out, usually a couple of days after they are cut off the tree. A lot of seed is actually viable for some time before it naturally drops and some species retain ripe seed for a year or more before dropping it so you can collect good seed for a large part of the year rather than just when it is dropping.

[Kevin]

I am surprised at the lack of success with germinating seed. They usually come up in thousands. Maybe we need to work on identifying ripe seed capsules and seed germination technique?

Hello Shibui,

At what development of the Eucalyptus seed capsules is best for viability and subsequent germination?
Are the capsules best collected whilst in their greenish phase of maturity?
Or are the seeds more viable within an unopened woody capsule.

I actually collected some greenish capsules from a E. microcorys and only older closed woody capsules from several E. tereticornis specimens, then either within a paper bag or tin used an oven at low temperatures or the heat from the sun to enable the capsules to open.
I have previously read that the capsules contain a considerable amount of 'chaff', not knowing exactly what 'chaff' looks like, i could of been sowing nothing. However, i did recognise or thought i recognised proper seeds, as i stated the E. tereticornis capsules were of considerable age no doubt.

The below photo illustrates what an immature Eucalyptus flower looks like. Unfortunately, i haven't any other examples of the capsules post flowering stages of development.
I believe you understand what i am trying to ask / describe, that is, unopened soft greenish capsules, like depicted in the photo or wooden unopened capsules directly from the tree as you described.

Which / what stage of the capsules development are best or viability and germination?

The purpose of the picture depicts almost exactly what a post flowering capsule looks like, obviously, without the capsules flower cap, but in the capsules colour and texture.

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Thanks,
Kevin

[shibui]

Seed pods change from green to woody brown in most species as the seed matures. For best result collect when the pods are brown or grey but before the valves have opened to release the seed however, as I said earlier, seed is often viable even when the pods are not quite brown. Obviously there won't be any seed in the few weeks after flowering - give them at least a few months before trying but best to wait until the pods change colour. Fully ripe seed is likely to be more viable and can be stored. Immature seed may grow if planted straight away but will not retain viability if stored. Fully ripe seed can be stored for quite a few years and will still grow.

From Aust National Botanic Gardens:

As gumnuts mature they change from green to brown and woody. Pick the brown woody fruits and place them in a paper bag in a warm position. The gumnuts release the seeds as they ripen. Separate the seeds from the chaff by gently blowing away the chaff. Eucalyptus seeds generally take about 2 weeks to germinate

I found some photos of mature euc seed capsules. Note that in these pictures the valves are all open showing that the seed has all fallen out so these are even browner than you'd normally collect.

euc capsules.PNG

This is what euc seed can look like.

euc seed.PNG

You mention 'chaff' which I forgot to mention earlier. If you have good eyes you can see the chaff in the upper left photo - the thinner, reddish bits. The black ones are proper seed. In the other photos it is quite difficult to pick the difference. Although the quote from the ANBG advises blowing the chaff away, in practice that is rarely done. Only the seed will grow and the chaff does not pose any real problem to germination. I just sow everything that comes out of the pods.

Most of the red gums mature and drop seed in early summer so I guess E. tereticornis will be similar.
Costermans lists E. tereticornis as flowering spring and summer as do the other red gums this side of the divide. Euc seed typically ripens around the time of the next flowering so I'd be trying to collect seed August - November for best results but you will need to check what's going on with the trees in your area.

In general:
Collect seed capsules when they change from greenish to grey/brownish.
Allow capsules to dry out inside a paper bag. Valves will open and seed comes out into the bag.
Sprinkle seed (or seed/chaff) on the surface of potting mix or Seed raising mix.
Keep mix damp until seed germinate.

[Kevin]

Thanks again Shibui,

Therefore ripe seeds will be present on 1 year old wood, when the tree is flowering.
I'll be on the lookout, especially after any storms.

Thanks,
Kevin

[Kevin]

Hello,

Just an update for the progression.

The E. tereticornis has tripled its size over Winter - Now at 700mm tall and 15mm trunk with lateral root development.
I will leave it until Summer before a minor root trim, pot on to a larger tub and a minor canopy reduction. That is, if it doesn't outgrow the present pot beforehand.

After looking at the photos is cage wiring the trunk to maintain the present curves recommended?
Any advice / opinions to the contrary is appreciated.

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Thank-you,
Kevin

[Sno]

Looking good Kevin . Nice radial roots . If you can find a safe spot on the ground you could let the roots run . Then it's a timing thing . You'll know when they have escaped because you will get quick growth . Then it depends how brave you are to when you lift and chop . I've seen great results with this method from Gavin G , he is a lot braver than I am .
Shibui 's slip potting method will work well too , the bigger the container the better . I've found that In a smaller size pot the trunk doesn't thicken much once it gets to a certain stage ,
I think you will find the movement you have in the trunk at the moment by the time the trunk thickens will be gone . The best way to get movement is chopping .
Cheers Craig

[GavinG]

For strong curves that won't grow out, cut hard, cut the branch you've cut back to quite hard, and remove most of the rest of the growth. Best time when things warm up - maybe late October? Then let one or two shoots grow long and strong for a year - that will give you maximum thickness. I'm not really sure about developing branches - flat pine branches just look silly. Many Eucs have a number of rising sub-trunks that ramify into a cloud. Good luck,

Gavin

[toshtony]

Tree is growing pretty quick nice job Have you cut the tap root yet? If not will and when will you do it? I have some eucs that germinated from seeds I collected and luckily a few weeks behind so this thread has been very helpful.

[dennismc]

Hi Kevin

I have been growing gum trees as bonsai for more than 30 years. If long term success is sought it is essential that the roots do not dry pout at all for 3 - 4 weeks after re-potting. If this technique is followed u can remove up to 50% of existing roots without a problem. Any taproot should be removed at the first root prune. NOTE: they do not like standing in water.

This technique will ensure that the gum tree should thrive. Now pruning that is another subject altogether!

Dennis Mc

[kcpoole]

I agree with Dennis,
Root prune seems to be OK but make sure not to dry out.
I have a few on the bench, ( no idea of variety, but self sown around my place) and have been ground a growing one for about 5 years now :-)and will lift it this year.
the ground grown one has been trunk chopped every year and wired in place.
It has been lifted and root pruned every 2 years I think so hope they are not too out of control.

Ken

[Rory]

Hi Kevin

I have been growing gum trees as bonsai for more than 30 years. If long term success is sought it is essential that the roots do not dry pout at all for 3 - 4 weeks after re-potting. If this technique is followed u can remove up to 50% of existing roots without a problem. Any taproot should be removed at the first root prune. NOTE: they do not like standing in water.
c

I completely agree. In regards to larger stock, I have not had problems with root pruning gums. I have placed them right back in full sun, but just made sure the roots were kept well watered and have not had problems either.
I usually allow the tree to recover for about 3-6 months at least after a major root cut.

It can take up to 4 weeks in some cases for the new shoots to appear after a root cut. Sometimes longer, so just be patient.

With seedlings though, I just remove the tap root, and again like Dennis says, I never let them get on the dry side after a root chop with seedlings. I always try to remove the tap root, and leave a small amount of fibrous roots on. But make sure you cut back the foliage if you remove a heap of the roots.

[Kevin]

Thank-you Shibui, Sno, Gavin, Dennis, Ken, Toshtony and Rory,

Your time, advice and experience in growing Eucalypts is extremely appreciated.

Also, thank-you for your compliments.
So far regular feeding, watering and sun gets all the accolades, my contributions into turning this young plant into a Bonsai is about to begin with the knowledge afforded to me from your generous contributions.

As for root pruning, besides an opps moment when transplanting where i lost 30% of the roots from the seedling tray to this container, no major roots have been pruned. I plan a pot on and pot up within the next few months where the tap root will be removed - hopefully with no more opps moments.

Kevin