Taxodium Distichum Part II

by Rudi Adam


1. Knees

After harvesting or maybe even before planting in the ground, it should be decided if the tree needs a special feature such as "knees" or if a more conventional root-system will do just as well. Knees will not happen in a bonsai pot, they have to be created êartificially. So far, no amount of keeping the tree submerged in water (fishpond or saucer) has ever created anything resembling this unique feature. It will therefore be necessary to create this feature in the early stages of the tree's development, while it is still in a large container or just out of the ground using a special technique. Timing is of the utmost importance, midwinter, the most active time in the tree season, is also the best time.

Select the tree of your choice; wash all the soil off the roots and select young, long and flexible roots that are no thicker than your small finger. Bend each root in an appropriate place and check the distance from the trunk and height of the artificial knee - mark the top and the sides with a Koki-pen. Cut the underside of the root with a sharp knife, as indicated in the drawing, now fold the wounded sides against each other, matching the cambium layer as closely as possible (at least on one side) and tie with raffia or water pipe tape, secure with stabilizing wire if necessary. Do not cut off the rest of the root. Repeat this procedure with 3 -5 roots, varying the distance of the knees from the trunk and the height of the newly created knees, diminishing the further they are from the trunk, but aim to make them as close to the trunk as possible. Shorten all the other roots and plant the tree into a large container for 1 or 2 years. When the bent roots have fused, remove the binding, but leave the tree in the large container or in the ground until the new knees are the desired size.

2. Roots

The main roots of the Taxodium are often very coiled due to the seed frequently being planted upside down or planted in too small a container, new developing roots are normally very straight.

Thick roots that are out of proportion or unsightly should be removed or they may be split in two or even three sections so that they appear in better proportion to the rest of the tree; this is done in mid-winter or the dormant time. Splitting a root is also a technique to use when a large root, which is no longer flexible can not be moved intact to new position. Remember to seal large cuts on roots to prevent the cut section from dying off.

Once planted in a container the roots tend to travel towards the sides and bottom of the container without utilizing all the soil. It is therefore imperative to repot frequently, every two years and a maximum of every three. This will prevent the roots from getting too thick and the necessity of always having to make large cuts.

3. Soil

Average soil with plenty compost and maybe a higher percentage of clay (for moisture retention) should be the norm. These trees are not very fussy about soil composition or pH, but they need constant moisture and can not stand any form of draught without visible discomfort.

Another new technological innovation in this waterproof country of ours is a product called "Soil Wet", little crystals that hold an enormous amount of water and readily release it to the plants when needed. Caution is advised - the crystals swell up from match-head size to fingernail size (holding 200gr water for every gram of granules). It is advisable to hydrate the granules first and then add them to the soil mix. Once hydrated it may be that the granules - now looking like "aspic" or jelly, may be too large for the container. You can push them through a medium sieve and only then incorporate them into the soil mix. When mixed dry into the soil they may pop to the surface after hydration and be unsightly.

4. Branches

While still in the ground the shoot that is bent from the upright to the ground may be pruned, without shortening its original length, to start developing the branches or side branches into pad like shapes. Leave the newly selected apical shoot intact. However, the more usual approach would be to train or treat branches only after harvesting and placing it into a suitable training container, as it is easier to see when the tree is at eye-level.

swamp-cypress-fig-7Figure 7. Bend branches only when desired size is reachedThe Cypress gains its aged appearance from three features: i.e. a heavy strong root system, rough fissured bark and strong descending branches. But like most young trees their branch structure when young is ascending making wiring in the initial stages an absolute necessity. Difficulties with branches that are larger than cigarette thickness may be encountered and it may be necessary to apply special techniques to overcome the problem of branches that look like upturned umbrella spokes.

The technique involves cutting half way through the branch at the trunk from above, which loosens the branch from the trunk and enables you to gently tear and manoeuvre the half severed branch into a descending position. Smaller branches may be cut from above with a side-cutter while larger branches may necessitate the use of a chisel. When this operation is complete it is wise to insert a small wooden wedge into the cut, as a spacer. Secure by means of wiring the branch from above so that it is stabilized and can not be accidentally knocked off, bend it in the correct position and trim any loose or splintered parts. Then seal the wound.

swamp-cypress-fig-8Figure 8. Bend new branches as soon as they are 200 - 300mm. Use lots of them.If left untrimmed for at least one season the Cypress will heal rapidly and may be completely healed over in 2-3 growing periods. The rapid healing of wounds is always in the same ratio to the speed and uninterrupted growth of the tree.

An alternative solution is to remove all branches that are thicker than pencil size on the entire tree and all the branches in the top 25% of the tree, allowing new shoots to sprout; bend them as soon as they have reached the desired length. The act of bending them downwards slows the growth pattern of the branch and they will remain slender for a long time.

5. Apex

Swamp cypress by its very nature, displays strong apical growth patterns and many of you will find it difficult to curb this pattern in future years. Simply pruning and re-establishing an apex every year will either result in the apical area becoming to large or in an uncontrollable upward expansion of the tree.

a) Establish a good taper, especially in the upper region of the tree.

b) From the last pruning of the apex select a suitable, but weak shoot, as your new apex - then trim it to about 3-5 ern. Allow it to sprout, select 3 side shoots and wire them to just slightly below the horizontal line and remove all other upward growth in the area. From this point on it is imperative that any new sprouts, be they apical or axillar especially in the upper half of the tree, are removed or at least pinched out in the soft stage.

c) Growth will happen where at first just leaves emerge - then weak and very strong shoots. Strong shoots with long internodal distance should be removed as soon as possible. Weak shoots and short sprouts may be trimmed back to any of the side leaves that point in the right direction once they have hardened off. Leaves should rather be left alone, except where they emerge on the trunk, which makes the tree look juvenile.

swamp-cypress-fig-9Figure 9. If existing branches are satisfactory - just shorten and use as frameworkd) Multiple sprouts should be thinned out as they emerge, because in time they will form knobby areas that will have to be removed at some later stage.

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Random Bonsai Tip

Sacrifice branches can be used to thicken up the branches or the trunk by taking advantage of the auxins in the terminal bud. A low branch could thus be used to thicken the base of the trunk and so improve the taper.