Dawn Redwood Fusion
Metasequoia glyptostroboides ( Dawn Redwood) Fusion Bonsai
In 1990 I purchased a Metasequoia glyptostroboides (Dawn Redwood) through the mail. What arrived was a pathetic bare rooted broken stick, so I planted it in the corner of my yard and ignored it. Fast-forward 18 years and that broken stick had grown over 60 feet tall and produced several hundred seed cones. During the late summer and fall I gathered the cones and tossed them in a shoebox for the winter. When spring rolled around I shook the box and hundreds of seeds fell out. Having read how hard they were to grow I was surprised to find that 156 of the seeds germinated. 100 of those seedlings survived through the first winter.
What to do with 100 trees? Planting 100 trees is quite a chore and disposing of a critically endangered species (IUCN Red List) like Metasequoia glyptostroboides was something I was not willing to do. There is an article by Doug Philips in a book titled Bonsai Master Class that demonstrated an approach grafting technique (referred to as fusion) of multiple Trident Maple seedlings to create a large trunk perfectly tapered bonsai in a very short time and I thought this might work with Dawn Redwood. I already had seedlings, so I experimented by wiring 3 pairs of seedlings together. In only four weeks the seedlings had all fused at the contact points where they were wired together. This technique will work with Dawn Redwood.
The first step of this project was to build a frame. Doug Philips had used heavy copper wire to essentially create an upside down tomato cage. I saw two problems here, first the cost of heavy copper wire is prohibitive and second it created too few anchor points to tie the seedlings to the frame. My solution was to use ½ inch galvanized screen ( hardware cloth) solving both problems. Notice how I flared the base to add character to the trunk.
On Feb 20 and 21, 2011 the tree was assembled using 2-year-old seedlings. The seedlings were bare rooted with all branches removed and roots trimmed. This is a 2-year-old seedling before cleaning and root trimming.
The next step involved attaching the seedlings to the frame. I tried to get the seedlings as close together as possible to shorten the fusion time by using thin copper wire to attach the seedlings to both the frame and adjacent seedlings. The wires will be left in place and the excess will be cut off after fusion is complete. I learned from my experimental grafts that removing the wires could cause the graft to separate. The roots were misted frequently to keep them from drying out.
I switched to paper wrapped wire ties half way through assembly because I found the thin copper wire ties to be too brittle. I had originally planned to use the paper wrapped ties but I could not find enough to complete the whole project. I randomly cut the thinner seedlings and covered them with larger seedlings as the frame gradually tapered to the top.
This is my little hollow tree viewed from the bottom. I kept as many of the roots as possible to accelerate growth and shorten the fusion time. I anticipate that this tree should be ready for a bonsai training pot after just one or two growing seasons.
The seedlings were weaved at the top with the excess to be removed after fusion is complete. Finally I placed the tree in a large pot.
37 seedlings attached to galvanized frame
Height – 31 inches Circumference at base- 25 inches
Total assembly time was 12 hours, which includes building frame, bare rooting seedlings, root and branch pruning, attaching seedlings to frame and potting.
I am fairly happy with the results of my first fusion project. However there are several changes I will make in future projects. First I will create frames with much greater contrast between the base of the trunk and the apex. This would require using one year-old seedlings instead of two year-old seedlings because the older seedlings were very stiff resulting in much loss of the flare I had designed into the base of the frame. One year old seedlings are much more flexible and would be easier to mold to the shape of the frame. This would require 100 -120 seedlings for the same size frame I used here. The seedlings would be shorter than the frame and would need to be attached as they grew up the frame. Secondly I would acquire prior to assembly enough paper wrapped wire twist ties to finish the project before I started. The paper wrapped ties are much stronger and easier to handle.
To get the buttressed trunk that I desire on this tree will require more grafting. NEXT YEAR!
This is the Dawn Redwood 1 month after assembly. Lots of buds have popped and branches are beginning to grow.
This is the Dawn Redwood at 3 months. The trunk (or more accurately 37 trunks) are completely covered with branches.
The Dawn Redwood fusion has showed very little fusion so far. The seedlings have not grown very much because I have kept them in a pot. I did not realize the impact that a very large pot would have on slowing growth. The 2 seedling test was kept in a pot and had very good fusion, but 37 seedlings in a pot created too much competition for space, water and nutrients to have much growth and therefore little fusion. A few seedlings have died off and will be replaced in the spring with extra seedlings that I kept in reserve. I will then plant the tree(s) in the ground and hope to see much better results.
Feb 12, 2012
Winter has been canceled this year. Well, maybe not, but we have sure had more than our share of 60+ degree days in Jan. and Feb. Last Thursday it was 62 degrees and I needed to get out in the sun for a while so I decided to work on my Dawn Redwood fusion project. After I originally assembled this tree last year it became quite obvious that the upper trunk was much too thick and had lost it’s taper. Since trunk fusion had only been modest I decided to correct this problem while I still had an opportunity. First I removed 5 dead seedlings and one near dead seedling, and then I separated the fusions, which at this stage had not fully hardened off and were relatively easy to separate. Finally I detached the seedlings from the frame and cut the frame down to 6 inches above the base. This allowed me to collapse the trunk.
The only problem I encountered with reassembly was that the seedlings were no longer seedlings but actually 3-year-old trees. Several were now approaching ¾ of an inch in diameter and the twist ties I was using would not bind the trees securely. My solution was to use small brass flathead screws. Most of the screws are hidden from view because I attached the trees from the side and the adjacent tree covered the screw. A few trees needed to be attached from the top and are visible. I counter sank these and they should heal over quickly leaving no visible presence. The smaller trees were bound by doubling up the twist ties. Finally I added 11 more trees/seedlings of various sizes to fill the gaps. The root ball (not yet root bound) was very solid and I planted it in the ground with very little disturbance.
It is hard to see the trunk in this photo because the trees exiting from the trunk are parallel to the trunk, however, the apex of the trunk is much improved and the taper is much more dramatic. The plan at this stage is to maximize growth this year and next spring begin removing the excess trees to be flush with the trunk.
You might be able to see that we had our first big snow storm this year. Not enough to cover the ground, but the cold has returned with a high today of 32 degrees.
The Dawn Redwood project is now over 6 feet tall. There is good fusion at the base but the apex has very little fusion because many of the twist ties have snapped and released the seedlings from their bonds.
Here you can see the fusion beginning to take hold near the base of the tree.
Here is a closeup on the other side of the tree. This is where I used a screw to attach the seedlings and it has held them together with pressure that can not be achieved with twist ties. The seedlings have completely healed over the screw and it is not visible. It should not be a problem to have screws completely embedded in the trunk because they are brass and will not rust. Even if they do eventually corrode the trunk will be completely fused by then. A problem might occur when I remove the excess whip of the seedling because I can’t see the screw and I could damage tools in the process.
Next spring I will insert many more screws to tighten up the trunk and apply the needed pressure for fusion.
Last year I was having trouble getting the larger trees to fuse. Several twist ties had snapped and were no longer holding the trees together. A few trees were now approaching an inch in diameter and twist ties were just not strong enough to hold them together. So I tried short brass screws and they worked great. In the pic above you can see that the large tree (right center) fused nicely to the one on it’s left after being screwed together. The only problem now is that because I counter sank the screw and the tree healed over the wound I can not find the screw. I am afraid that when I remove the excess whip down to the trunk I will find the screw and damage my pruners.
So this time I used 3 inch long deck screws. This is the apex. The plan is to carefully remove the screws after fusion is complete and I don’t have to worry about cutting into one of the screws.
Farther down the tree you can see I used several screws, 8 deck screws plus 4 more brass screws from last year. There were several areas that needed to be locked down with pressure to force them to fuse. No pressure, no fusion. Note that the bottom screw actually goes through 4 trees.
My friend Shane Martin ( http://shanemartinbonsai.wordpress.com/2013/01/) used a brad gun to shoot nails into half inch diameter seedlings to attach them to a wooden frame. He said it works great. I will follow that project closely.
There are many ways to attach seedlings together. The important thing is to apply constant pressure. Thin seedlings are easily held together with wire, but as the seedlings get larger they often snap the wire releasing the pressure. If that happens you need to get creative.