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.

3 Responses

  1. crust

    I too have tinkered with approach grafting Thuya with Chama. My impressive, supercool experiments failed, of course, sometimes when I removed the mother foliage and sometimes by just not taking. One smaller projects lives on though. I used a dwarf variety and found it is excruciatingly slow. I agree that a zippier variety like ‘Kosteri’ is a better way to go. I found that when grafting onto old Thuya stock the Thuya had to be revved up enough to have nice thick luscious skin.

    July 29, 2012 at 10:42 pm

  2. lackhand

    Just wondering if there was a follow up on this graft? Thanks!

    June 25, 2013 at 1:21 pm

    • Hi Lack,

      I will post an update in the next few days. Last years graft is looking promising but not quite ready to separate.

      June 25, 2013 at 11:14 pm

Leave a Reply

Your email address will not be published. Required fields are marked *