Tuesday, 22 September 2015

Bonsai Cultural notes for October 2015

A segment on the recent Gardening Australia program featured a crusty old citrus expert “Mr Citrus” who showed the bare rooting of a young tree for planting. When asked about the best time to do this he said something to the effect that “when the temperature hits the magic 14 degrees you start to get root development.” That means we could do so here at pretty much any time of year. My yardstick is 12 degrees overnight and so had all my root work done this year in mid August.

Trees that were bare just weeks ago are now covered in fast developing foliage. Even the figs which I did at the same time are just sprouting a new coat of bronzy green leaves. Once the first flush of growth hardens off there’s no reason why missed treed can’t be root pruned in the coming months.

But the task at hand now is managing all that abundant growth. If you didn’t reduce the shoot density as they emerged then these will now be lengthening. With better visibility of these now the thinning process can still be done, but does need to be done. We need to avoid turning branches into ‘toothbrushes’ with too many fine branches too close, and we have to prevent the apex or canopy of our trees becoming too busy,  constricted and flawed.

Where structured branch development is a priority the shoots that are retained need to be directed – with a little wire. These ‘selection’ and ‘direction’ tasks are the most important October bonsai jobs. 

A first application of fertilizer is a close third.

Where you have a tree at the height you want to keep it then slowing the top is always a priority and encouraging growth lower in the tree. You may selectively tip prune those at the apex while allowing those on lower branches to extend for many weeks, particularly if you are trying to correct any dis-proportions in the tree. This is also a good time to encourage a sacrificial branch on the trunk or a lower branch to also address proportions.

I accumulated many native species over the winter as well as some more in the ‘native buy’ run by the club. Some of those that were fairly stout tube-stock, like the Melaleuca bracteata, have shown good root development and were starting to put some shoots out lower in the tree. I’ve now cut the trunks of these off at about 150mm long and anticipate many shoots emerging on the bare trunks. I’ll be looking to identify a new leader and a sacrifice branch from the new shoots, wire them up for shape and let them grow for at least 8 weeks before any more work. Pruning like this gives more shoots than we need but they offer options for development. It is important to only keep the ones that will help the development and direct the bulk to where we want it.

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