Judging by the number of trees that our members brought, I think we may be able to consider separating these species out another year! It was however lovely to see the trees, each with a story to tell and some discussion to be had about it.
The humble but majestic oak is a feature of our British countryside, and it is therefore not a surprise to find that it is also quite a popular species for bonsai. The trick with oak is to work on its leaf size. It will often send out large leaves, out of keeping with the size of the bonsai, but there is a way to battle this. Make a note to come back to this page before your trees leaves break to make the most of the following advice!
The key is to watch your tree for signs of the buds swelling. Study each growing point carefully, and you should see a dominant strong dark coloured bud with at least one, but maybe more little buds behind it. Remove this dominant bud at this stage (usually late January/early February) and leave behind the smaller bud. By removing the dominant bud just at bursting stage, this will throw some energy back to the next couple of buds but it will give them less time to grow big, so it should produce smaller leaves. This can be continued throughout the year with a healthy oak, each time the leaves will be smaller. This must be repeated each year though, feeding and health affect it, or the tree will just create large leaves again. Once the leaves break, if you do not want to develop the branch, cut back to 1 or 2 leaves.
The beech only has one flush of leaves, very different to the oak, so you only have one opportunity. If you are maintaining a tree or you want to promote back budding, you will need to ensure you pinch out the growing tip before it extends. As it grows out in the early soft stage with the down on the leaves, you will see a number of leaves appearing on the extension, but you need to stop it at the last pair of leaves while the growth length is fairly short. Once it has extended, you are too late.
Be warned. If you are not checking your trees almost twice daily in early spring, you will miss your opportunity!
The ash, including the mountain ash (rowan), have a slightly different leave format, and this adds extra issues as each individual leaf can become incredibly long. To reduce the leaf size and remember it only works for that growing season, pinch out the growing tip after 1-2 leaves, depending on whether you are maintaining or growing that shoot. When the next shoot appears, pinch it back after one leaf. Once this has opened, you will see that it is smaller than the original leaves. You can then remove the original leaves, and this will give the effect of smaller leaves.