In the wild, Acacia’s form all sorts of shapes, but the classic on is the flat or dome topped shape so often seen in photographs. This variety of shapes is caused by the action of grazing animals and it is this response that the grower hopes to harness when growing bonsai forms of these trees.
Germinate the seeds as stated in the separate instructions, but try to sow one seed per small pot – the reason for this is that they do not like much root disturbance, so this will be the pot you start off with in your attempts at training. Allow the tree to grow to around 1.5 times the height you want your bonsai to be. So if you want a 1 metre tall tree, let the seedling reach at least 1.5 metres before pruning starts. If it outgrows the small pot, then move it up one size with care not to disturb the roots too much.
The first cut should be to remove the growing point of the leading shoot to the actual height you want (so in the above case, take off ½ metre to leave a 1 metre tree). Then you can carry on by shortening side shoots to form a branch structure and a crown. Take it slow and easy here, try to allow the tree to recover from each cut.
It is long term results you seek not a short term instant fix. Shoots forming below the crown can be removed immediately, indeed if you see the small green buds on the main stem in the wrong place, it is better to remove them by ‘rubbing them out’ while still green and soft, rather than to wait till they are branches and cutting them off – this provides a better finish. Because they are fast growing, you can achieve excellent results in around 4 – 5 years.
The minimum height for these to thrive is around 30 – 45 cm and the maximum can be whatever you want. If you want to grow a bonsai forest then you have two options. You can either grow your seeds in a shallow tray, in which they will stay as the ‘forest’ grows until such time as you put it into its final display pot/slab or you can grow the trees individually and then mount them together when they are ready. The 1st method looks more natural, the 2nd method gives you greater pruning control. Each has its merits so you can decide which is best for what you want to achieve.