Grafting

Larch Thread Grafting Woes

Most of the old crusty larches I collect need grafting. It seems the older they are, the farther the living foliage is from the interesting part of the trunk. Three thread grafts were started on this larch in spring 2014 and all three of them failed this summer (despite not yet being separated from the donor branch).

Three dead grafts. The middle one was the most important as that was to become the new leader of the tree. The one above that... well it was too high i.e. a mistake.

Three dead grafts. The middle one was the most important as that was to become the new leader of the tree. The one above that… well it was too high i.e. a mistake.

 

I’m not sure why they failed, but I think it might have had something to do with long period of time elapsed. Ideally, once started, a thread graft will grow rapidly and then take within a few months. Unfortunately, these grafts hardly elongated last year therefore they had no change of reaching the thickness required for fusion until they really started to take off this year. But in July of this year when they should have been fusing, they were instead girdled and died. This is purely anecdotal, but I believe that the callus that formed around the edges of the drilled hole was somehow too hardened-off or otherwise too old to readily form a graft union with the threaded branches by the time they were thick enough to do so. Or maybe the drilled hole didn’t form a callus at all.

Anyway, they failed and I needed to re-graft. Late summer is not a good time for thread grafting larch, so I tried a traditional approach graft instead.

I'm not sure what these nails are really meant for, but in Japan they are commonly used for grafting. Here they are not going through the branch, but are just adjacent to it. With thicker branches it is OK to hammer them right through the branch.

I’m not sure what these nails are really designed for, but in Japan they are commonly used for grafting. With this graft they are not going through the branch, but are just adjacent to it. With thicker branches it is OK to hammer them right through the branch. They do an outstanding job of creating a very snug graft junction.

And now we wait...

And now we wait…


Grafting Hinoki on Thuja: Round 3

In Spring 2012, I tried bud grafting hinoki foliage on a scraggly collected Thuja, which failed. Later that year, I tried approach grafting hinoki foliage onto the same plant. Over one year later, the results are still unclear. The approach graft is alive and well, but it has not clearly fused with the Thuja tissue. I have a feeling the wounds on scion/stock both just healed over instead of grafting with one another. At this point I would say the approach graft was not successful.

Not convinced that this approach graft has taken.

Not convinced that this approach graft has taken.

Nevertheless, I left the approach graft in place and moved on with my third attempt of grafting this plant with a third type of graft: the One-Point aka Single-Point Graft.

One-point grafts are very similar to thread grafts, except defoliation is not required. This makes this type of graft a very useful tool for conifers. Many years ago, I successfully one-point grafted my Canadian Hemlock (Tsuga canadensis) after learning about this type of graft from Nick Lenz’s Bonsai from the Wild 2nd Ed. In fact, Nick hints at one-point grafts as being appropriate for Hinoki-Thuja operations, but first describes them in his larch chapter:

A variant of [thread grafting] is the one point graft. Instead of passing a bald branch through a hole in the trunk, you fold over a branch and squeeze it into the hole. Before insertion, you scrape the outer edge of the fold with a thumb nail to remove the cambium. When jammed into the hole, the cambium layers of the drill-out and of the scraping will touch and merge quickly. This approach has several advantages. You can perform it at any time during the growing season as the branch does not need to be bald. This is especially useful in species that grow out but once in a season, such as pines. It also takes less time to complete. You do not have to drill all the way through the trunk, but only a centimeter or less.

The disadvantage to this approach is not great. The branch may be fatally injured when folded over. If this happens and the new graft begins to dry and brown up, you can readily pull it out and try again with a smaller branch. Despite the tendency of a branch to break (crack) when doubled over, you can always find one that will tolerate the procedure. Success is more likely on hot, dry days when water is withdrawn from the wood. -Bonsai from the Wild 2nd Ed., p. 33

A few weeks ago in mid August I looked disgustingly at my still-ungrafted Thuja and grabbed my drill. Three one-point grafts were initiated and today they all still seem to be alive. Basically what I have now are three thread grafts in my Thuja, and hopefully now it is just a waiting game.

A one-point graft that seems to have survived the initial folding-and-cramming.

A one-point graft that seems to have survived the initial folding-and-cramming. The scion for this graft was growing off the scion used for last year’s approach graft.

Another one closer to the base of the trunk.

Another one closer to the base of the trunk. All of the one points were slathered with some Japanese wound sealant which is pretty much white glue.

I'm not sure if this tree is even worth all the trouble. Sure, it will be nice if I can make it a bonsai, but this grafting project now seems more about me proving to myself that it can be done.

I’m not sure if this tree is even worth all the trouble. Sure, it will be nice if I can make it a bonsai, but this grafting project now seems more about me proving to myself that it can actually be done.

 


Thuja Grafting Round 2

Well, my attempt at bud grafting hinoki on this Thuja in the spring failed quite miserably. Of the three scions I grafted, only one actually started to push new green tips, but it soon fried once the heat of the summer arrived.

Here is my attempt to use an approach graft. Approach grafting on junipers is often done in the summer. I know this is not a juniper, but I think that Thuja and junipers have a lot in common in terms of their physiology. I have no evidence to back that up except for watching them grow in my garden over the years. I think the summer is a good time for grafting because this is the time when the trees are really throwing out new wood/callus tissue and wounds close up quickly. Also, sap flow is very high. I’ve done some thread grafting on deciduous trees in the summer with good success. I wouldn’t try any sort of bud grafting in the summer as the scion would probably get fried really quickly.

Here is the poor bastard, nice and healthy but dying for some foliage closer to the trunk.

Here is the poor bastard, nice and healthy but dying for some foliage closer to the trunk.\

The first step was carving a channel using a dremel set at low speed with a sharp cutting bit. I did my best to make the channel the same diameter as the scion, and the depth was about half that. The wound was cleaned up with a grafting knife.

The first step was carving a channel using a dremel set at low speed with a sharp cutting bit. I did my best to make the channel the same diameter as the scion, and the depth was about half that. The wound was cleaned up with a grafting knife.

Here is the plant that I am trying to graft to the Thuja: Chamaecyparis obtusa ‘Kosteri’. A really lovely variety and somewhat stronger than ‘nana’.

The next step was securing the hinoki and Thuja containers together. In this case I simply rested the hinoki pot on top of the Thuja and tied the two together with three strong guy wires until they were rock solid. It is very important that they are securely mated so they can be moved around together through the seasons. Even in the best case scenario it could be a year or more before the two are separated. It would have been easier if I had hinoki cuttings in small pots, but this is the only material I have to work with. Making a bunch of cuttings of this variety for future grafting attempts is on my list of things to do.

The next step was securing the hinoki and Thuja containers together. In this case I simply rested the hinoki pot on top of the Thuja and tied the two together with three strong guy wires until they were rock solid. It is very important that they are securely mated so they can be moved around together through the seasons. Even in the best case scenario it could be a year or more before the two are separated. It would have been easier if I had hinoki cuttings in small pots, but this is the only material I have to work with. Making a bunch of cuttings of this variety for future grafting attempts is on my list of things to do.

Here is the branch to be grafted with the bark scraped off to expose the green cambium. It is probably a 2 year old branch. Before scraping, make sure you do a test fit to make sure you are scraping in the right place!

Here is the branch to be grafted with the bark scraped off to expose the green cambium. It is probably a 2 year old branch. Before scraping, make sure you do a test fit to make sure you are scraping in the right place!

I fit the scion into the channel and secured it in place with two wires with some protective rubber. It must be very tight. Try pushing on the scion - if it still flexes into the channel, it is not making good contact and must be tightened. The whole thing was then covered in grafting wax.

I fit the scion into the channel and secured it in place with two wires with some protective rubber. It must be very tight. Try pushing on the scion – if it still flexes into the channel, it is not making good contact and must be tightened. The whole thing was then covered in grafting wax.

Next, I covered the graft with a small piece of damp sphagnum moss, and covered that with a piece of plastic mesh which was secured to the trunk with three wires. The purpose of this was twofold: 1) to protect the moss from birds and drying out too quickly, and 2) to distribute more even pressure over the graft.

Next, I covered the graft with a small piece of damp sphagnum moss, and covered that with a piece of plastic mesh which was secured to the trunk with three wires. The purpose of this was twofold: 1) to protect the moss from birds and drying out too quickly, and 2) to distribute more even pressure over the graft.

Here is the happy couple. The graft is circled in red. You can see that I did some trimming of the foliage around the graft to create a nice opening so the graft will still get good sun exposure.

There are lots of types of approach grafts, but I chose this method because I like the idea of the long channel creating a lot of surface area for cambium-cambium contact. No matter the method, I think the key points are to get good cambium contact, and lock the graft into place so it absolutely cannot move.

If the grafted branch continues to grow, that is a good sign but does not mean much. It will probably be next spring before I take a peek at whats going on underneath.


Korean Hornbeam Cutting

I’ve been developing this carpinus from a neglected stump for about 6 years. Most of the primary branches had died back under the previous owner. I have been trying to build a new tree from thread grafts. It is coming along, but slowly.

Korean Hornbeam need to be cut back later than maples, otherwise they won’t backbud well. Usually this mean late spring, once the new growth has hardened off. This is also a good time to send through some thread grafts as defoliated branches will bounce back quickly, and smaller holes can be drilled since winter buds have not yet formed.Thread grafts can also be sent through in the late winter, but larger holes need to be drilled to get the branches through without rubbing off the large winter buds.

Healthy spring growth. I was planning on repotting this year, but never got around to it.

Leaves have just hardened off in the last week.

After cutting back. The tree will be moved to a sunnier location and fertilized heavily to encourage backbudding.

This branch was thread grafted a few years ago.

This is the first branch I threadgrafted on this tree. Funny that it is now supplying the whip for this year’s thread graft (note small branch wired inward)! Ahh… the circle of life… :)

This years little threadgraft, growing well. Note the size of the hole. This is the disadvantage to sending threadgrafts through in the winter. Larger hole = longer time period before the scion is large enough to start fusing with the trunk.

Some fruiting structures (catkins?) were spotted and removed. The branches that these grown on weaken dramatically. I try to remove the conspicuous flowers in the spring, but usually miss a few.


Grafting Hinoki on Thuja (Arborvitae) Part 2

See here for Part 1.

My Thuja are starting to lose their winter colour, so I figured now was as good a time as any to make my first attempt at grafting hinoki foliage to this old bare tree.

Ready for grafting.

Ready for grafting.

The type of graft I attempted was a type of side veneer graft, as shown in the image below.

Side veneer graft.

Approximate size of the scions used. Hopefully they aren't too big? I chose the size based on images I've seen of people doing the same type of grafting on juniper.

Approximate size of the scions used. Hopefully they aren’t too big? I chose the size based on images I’ve seen of people doing the same type of grafting on juniper.

 

A (very tight) elastic band was used to initially secure the scion to the rootstock. This is a nice trick I learned at a recent grafting workshop. It allows you to still "tweak" the position of the scion after it is secured to the tree, to ensure that the cambium is aligned properly. There are special UV resistant elastics designed for this job, but I just used old kitchen elastics. A tight layer of teflon tape went over the elastic to protect the wound.

A (very tight) elastic band was used to initially secure the scion to the rootstock. This is a nice trick I learned at a recent grafting workshop. It allows you to still “tweak” the position of the scion after it is secured to the tree, to ensure that the cambium is aligned properly. There are special UV resistant elastics designed for this job, but I just used old kitchen elastics. A tight layer of teflon tape went over the elastic to protect the wound.

Three grafts in total were attempted. One was covered in a clear plastic bag. For another, the scion was wrapped in parafilm (which apparently breaks down quickly enough that the scion can actually grow right out of it). The last one was left unprotected. Professional propagators don’t wrap their scions in anything, but they also have fancy greenhouses to control their environment. We’ll see what happens.

To be honest, I am not feeling very confident about these grafts. I did the best I could, but I feel that I am at a big disadvantage without having a greenhouse. But nothing ventured, nothing gained – right? If these fail, I will try approach grafting and possibly some more side veneer grafting in the late spring.

Fingers crossed!


An Incredible Grafted (Setsu-goyou) Miyajima White Pine in Japan

Grafted Miyajima White Pine (Pinus parviflora) have a bad reputation because it is difficult to find a specimen with a smooth graft between the black pine base and white pine top. This is probably because the black pine base grows faster and more strongly than the white pine top.

While visiting a private garden in Japan, I saw this masterpiece grafted miyajima white pine. The trunk line was practically flawless, with hardly any swelling or unsightly graft transition (unfortunately not visible in the picture). This is rare even in Japan, making this a very special tree.

To make things even more incredible, the owner told us that this tree had not been detail wired in nearly 30 years! I found that almost impossible to believe. That would be the ultimate display of bonsai maturity and maintenance techniques.

Masterpiece grafted (setsu-goyou) Miyajima White Pine