Dealing with Difficult Roots

The conventions taught in the United States through books, magazine articles, and “Master Weekends” for decades have mostly dealt with the treatment of either nursery stock or pre-bonsai stock. Both types of tree can tend to possess compacted root masses in the shape of their respective pots. Nursery stock is mass-produced with size and salability in mind, so with one notable exception[1], they produce masses of roots that circle the pot and must be dealt with. While pre-bonsai may have nebari that have been worked on in the past, to give the root spread sought by the artist, the remainder of the roots will probably resemble a nursery tree.

In either situation, securing the tree into the pot is normally just a process of deciding exactly how to tie the root mass into the pot. There will be enough root to get a good purchase with the tie wire in any of several ways.

This happy circumstance rarely exists with collected trees. Often, the natural growth pattern of the tree has been affected by its surroundings, and less-than-ideal root placement appears to be the norm rather than the exception. Many collected trees have very few roots, or roots that require massive intervention if the tree is ever to reside in a bonsai pot.

So how does the hobbyist or artist deal with one-sided, sparse, or ugly roots?

“Square Roots” Method

This is the fun name given to the use of dimensional lumber in the pot to support the tree and secure it where there are no roots in suitable places.

This collected Ponderosa pine is typical of such material. The big box was specially built for it since the roots move in one direction: directly under the trunk and foliage. It’s no secret why this happens. Perhaps the tree was in a pocket of stone that prevented roots from moving in any other direction. There may be other scenarios, but the point is that this tree is magnificent, but has difficult roots.

If you look carefully, you may see that what seems to be the base of the tree (toward the left side of the pot) is really just a loop in the trunk. The base is actually at the far left end of the box, close to the uprights for the cart. The roots extend from that point, all the way to the other end of the box. It was time to work on this tree.

It’s always a challenge to work on a tree this size. This one, including the box, must have weighed over 200 lbs, so an extra pair of hands and a strong back is a must!

The goal on this repotting was to remove the remainder of the mountain soil and get it into a bonsai pot for its further training. In order to do that, we dismantled the box a board at a time. Feeder roots had just about filled this box, so it was obvious that the tree was spectacularly healthy.

John began by combing out the tips of the feeder roots from the outside edge, working back toward the trunk. We wanted to tease the roots out, keeping as much as possible to continue the strong growth and back budding of this tree. One of the easiest ways to accomplish this is with a pair of angled-tip tweezers held with the points open. It’s easy to control, the tips do very little damage if they are handled with a light touch, and one gets two tips, each doing the same work of one chopstick in the process.

There were still some long thick roots that had little or no feeder roots depending on them, so we were able to shorten them considerably. Remaining mountain soil was removed using a combination of tweezers, high pressure water stream, and hand manipulation. The key was to avoid too much harsh treatment of the new feeder roots, while cutting back useless older roots that were difficult to fit into a pot.

From beneath, you can see just a bit of the discoloration from the old soil. Surrounding this core is the mass of fine feeder roots that have made the tree so strong. It cannot be emphasized enough, how important it is to eventually remove every bit of old soil, in order to make the most compact, vibrant root mass possible.

This view shows the main difficulty with this tree. The roots are entirely one-sided, a fact which was exacerbated a bit by being planted so tightly to the side of the box. This arrangement makes securing the tree in a bonsai pot a bit more challenging than the usual scenario. Since the shape of the tree exerts an upward pressure on the root base back here, we wanted to secure it in such a way that the tree would not move at all, and would thrive in its new pot.

Once a pot was chosen for the tree, John set about adding drainage holes with his drill press fitted with a carbide hole saw. These are fairly inexpensive pots, and the drill press breaks out a bit of material on the inside, but in general this is an excellent way to improve the drainage, especially of such a large pot. Water is added to keep the drill biting and to reduce heat buildup.

Arranging the roots while keeping as much of the feeder root system as possible was the next challenge. The roots were very long, yet we needed to keep as much as possible to continue the strong growth of this tree. John tucked roots in, spreading them out much as practical to give them maximum advantage.

Now was the time to put the “Square Roots” method to use. Because the tree wanted to tip over in the pot, John secured it using a small piece of lumber on one side, and a larger piece under the opposite side to support it in the proper planting position. It was then tied in place with copper wire to make it completely secure.

The repotted tree is very secure in a much smaller pot. This is very difficult to do without some kind of extra supports inside the pot. Don’t be afraid to use whatever will work

The purpose of this article was not to provide an instruction book on how to fix one’s tree. Every set of collected roots presents its own challenges and rewards. Creatively using a basic knowledge base is the key to making these things work and planting your tree in the best position for future styling.

Darrellw[2], of Vancouver, WA (the screen name of a member at www.bonsainut.com), has used a similar technique on a collected Ponderosa pine. The tree as collected was wired against the side of the pot to support it.

Darrell repotted the tree into a plastic container, and used a slightly more refined technique to give it that same support. He beveled a piece of 1”X2” stock and secured it across the corner of the pot, using that to anchor the trunk.

It is easy to see why the tree needed extra help in being secured to the pot: the roots were sparse and weak, and would not have held had they been wired into the pot themselves.

By using the “Square Roots” method, his tree has thrived and promises to become a great bonsai.

Here is another example of “Square Roots.” This tree has been planted in this position only with the help of stilts that reach to the bottom of the pot. This was done mainly with the intention of providing the optimal planting angle for the styling of the tree. Having worked on the wiring of this tree, I can attest that it is very firmly secured in its pot!

When the time comes to display this tree, the stilts could either be replaced with a stone or camouflaged in some way. The tree could be repotted more deeply, but that would necessitate a much larger pot, which might me out of proportion with the tree itself. Only time will tell what the ultimate solution will be for this tree.

Finally, this large juniper has been potted using the same method. This will be a temporary solution for this tree, and the eventual permanent potting will not show the braces.

Conclusion

Securing your tree properly in its pot is one essential aspect of ensuring that it not only survives, but thrives. To that end, any type of support in your pot that makes it better for the tree and a more appropriate planting position is fair game.

It is certain that there are other good methods for working with poorly placed and weak roots. This is merely one more tool in the belt of the bonsai artist. Done well, it can improve your tree’s ability to develop well.

Good luck and good bonsai!

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[1] Forrest Keeling Nursery, just outside Elsberry, MO, has been pioneering the use of air root pruning on a production scale. http://www.fknursery.com/index.cfm/fuseaction/home.showpage/pageID/18/index.htm Accessed 04/21/08

[2] Darrellw, http://bonsainut.com/forums/showthread.php?t=371, photos used by permission.