Today it was time to perform a chore I’ve really been anticipating – and not in a good way. My very big American hornbeam, Carpinus caroliniana, has been in its training pot now for three years. Hornbeams root vigorously in a bonsai pot, so this chore could not wait another year.
In this first photo, I’ve removed the tree from its pot and placed it on the potting bench. The soil surface is covered with moss, and there are numerous weeds that also have to go.
The first step was removing the moss and plucking weeds. This step is also where you get to figure out how healthy your roots are. There are some very simple, telltale signs that tell you there are problems in the root zone. One is actually smell. If you have root rot, it’s going to stink. The roots will also be black and mushy to the touch, pulling away in nasty clumps. Healthy roots are usually a light, orangish-brown color (as the ones you see here are). If your soil is properly composed, they will appear as a fibrous network. They literally run all over the place! This is both good and bad. If your repotting goal is to straighten out roots, as it should be if you’re developing your nebari, much time will be spent teasing the roots out of the soil mass. If, on the other hand, you’re repotting to refresh your fibrous root system and give it room to renew its growth, your work is simpler.
Another thing you need to do when repotting your trees is to work on any defects of the surface roots. In the case of this tree, I have two that are regrowing from their original chops. This one has smaller sub-roots growing from either side of the chopped root. I made a cut into the end of this root years ago with my knob cutter, in order to begin the process of subdividing the root to make it look more natural. Today I need to continue this work.
This one, on the other side of the tree, needs more attention. Time to pull out the dremel and carving tools.
In a few minutes, I’ve carved a narrowing groove up the root. This helps to visually correct the abrupt appearance of the root chop. Over time, this wound I’ve made will start healing over. As it does, I’ll come back and carve down into the center more deeply. Eventually, this single root will appear to be a branching root with good taper.
Back on the other side, I’ve continued the process I just mentioned by carving higher up on the root and carving down through the center of the root near the end where it was originally chopped. The two sub-roots will continue to thicken, in time making a smooth appearance.
Time to reduce the root mass. Here’s the fast, easy way to begin this process. I highly recommend it for large trees.
Less than a minute later.
The bottom gets it, too. I need to cut half of the depth off the root mass.
Now we’re just about ready for our new pot. The permanent home for this tree, a nice Byron Myrick rectangle, is a bit smaller than the training pot. So it took some additional trimming to provide room for the necessary fresh soil all around the tree.
The end-result. An impressive, beautiful tree in a fine bonsai container. Notice the position of the tree, slightly to the right of center so that the movement takes the apex over the opposite side of the pot. It’s a little hard to see in the photo, but the tree is potted slightly to the rear of the pot. The depth of the pot matches the trunk thickness, 6″. And finally, the length of the pot is about two-thirds the eventual finished height of the tree. Proportion is essential to proper bonsai design.
One final note: in order to further improve the appearance of the surface root on the right side of the tree, I carved it down a bit to create just a little taper in the main part of the root. It’s a subtle change, but I think it does help.
What do you think of this tree? Leave me a comment below.