ROR Korean Hornbeam Fusion

[Johnnyd]

So I picked up this Korean hornbeam root over rock project. It looks like 3 sapplinigs were fused together and tied to an interesting rock. I don't have experience with root over rock. I have heard that the roots are supposed to be exposed slowly. My initial response was that I would simply airlayer it off the rock. When I popped it out the pot to roots looked very promising. Lots of movement along the rock. So my new plan is to keep the ROR.
One problem I see with the base is that it is not completely fused together. For now I thread grafted 2 additional saplings to the base and wedged a 3rd between the rock and the base. Also gave it a bit of a hard prune and slipped it in a wider container.

 

[Johnnyd]

I was been searching for information late winter to see if you can thread graft or approach graft Korean hornbeam.
All graft joined with no problems. I'm still trying to figure out a style.(I'm between multi trunk and informal)
For now I'll see if these seedlings can help fatten the base. Also they may help the roots attach to the rock. I'll have a look at the roots progress when I repot this summer. I have heard from senior members of my club that kh take a long time to attach. I'm interested in any feedback from members here who have experience with this.
I really like the species. They seem to be trouble free!

 

[JudyB]

If you allow free growth of the tree, they seem to speed up. As in let it grow wild for at least one season, sometimes it takes free growth for more than one season to spur faster growth. That's what I have seen anyway. There does seem to be two types of these, I've had several that were rampant growers, and some that were pretty s l o w...

 

[Johnnyd]

Want to update the question about grafting and the progress so far. I did find thread grafting to work well. I used Judy's advice and grew it freely. This also helped it attach solidly to the rock. I ended up only keeping the one low graft on the right in the design. The tree was slip potted into a 3 gallon container in 100 percent akadama which also aided root growth. Now I'm trying to encourage the roots to further fuse. I'm hoping for a melting roots effect seen on trident maples. I used some string to bundle the small roots close to the main root. Anyone else trying ROR Korean hornbeam?