soltan wrote:As you can see this will not be an easy task. The base of these trees are going to need alot of work.
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I am wondering wich is the best way to get away from the bulging lignotuber.
How long will they take to grow out is there any way I can sepeed it up.
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looking optimisticly some of this could be intresting under there but I think the truth will be just alot of trouble
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Is ground layer a possibility on these?
Gday Brettles!
Sorry it's taken a while for me to get in and comment, but I've had some IT issues of late and am just getting back on my virtual feet...
Ahhh, the lignotuber: the bane of Euc Bonsaiists world wide... It
can be a great feature, providing fat, gnarly basal flare, but more often than not an exposed lignotuber is a troublesome and ugly bulge. I imagine that one could write an entire Master's thesis on lignotubers and still not be able to fully explain their function and behaviour. That said, I'll attempt to convey what I have learned about them in my few years of fiddling with Eucs.
Let's begin with what it says in the Oz Native Bonsai Bible:
Dorothy & Vita Koreshoff * wrote:
Some Eucalypts, along with a few other species, produce a swelling starting either under of above the soil around the base of the trunk, called a lignotuber. This is made up of undifferentiated cells, which, depending on the conditions surrounding a particular part of the tuber, have the ability to either produce branches or roots. One of the important factors ensuring successful rootpruning is, UNDER NO CIRCUMSTANCES should the roots, trunk or lignotuber be planted deeper than the original level of the soil, otherwise the tree will surely die. There is no danger from exposing MORE of the tuber or root.
* Bonsai with Australian Native Plants, p.49-50
Taken at face value, the Koreshoffs' statement would have it that there is little or nothing you can do to correct the reverse taper displayed in many of your Eucs. However - as is so often the case in Bonsai literature - the Koreshoffs do not make mention of the age and type of tree that this rule is based on. It is my assumption that they are talking about old, established trees collected from the wild, and not young nursery grown trees like yours. I believe that there is a more-or-less direct correlation between the age of the tree and the sensitivity of the lignotuber to soil depth. It is
my experience that younger Eucs can be planted deeper than the original level without harm, and that by doing so they can be made to produce roots higher on the lignotuber, or even above it.
Without seeing each tree first-hand, my first course of action would be to attempt to
hide the problem, by raising the soil level in the pots to
just above the fattest part of the lignotubers. (It is clear that most of the pots have lost a good amount of soil depth due to surface erosion and soil compaction, so it is really debatable exactly what the 'original' soil level actually is: it could easily have been another 30-50mm higher in comparison to the trunk/tuber.)
Brettles_Euc_Soil_Virt.jpg
Ground layering could be a good option, but I my experience with layering Eucs is confined to layering high on the trunk. Ideally, you would attempt a ground layer just above the lignotuber, so that the roots you achieve would cascade down over the tuber, giving you instant taper. Even better than attempting a layer above the lignotuber would be to layer at the fattest part of the tuber using the
skirt layer technique so that the initial bulge of the lignotuber might blend smoothly into a nice, radial root spread.
However, I am uncertain how a Euc would respond to injury so close to the lignotuber. I'll try to get my hands on some similar material and try some experiments.
In the meantime, I'll be watching this post for your progress, especially with those couple of clumps. Bear in mind that it is crucial to get trunk movement happening as early as possible when training Eucs.
Good luck, and keep us posted!
Fly.
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