Thread Grafting
By: Jim Beck—March 2021
I have had this Ficus for some time. Recently a key branch died. I have decided to replace it with a length of another branch using a process known as thread grafting. I will thread the donor branch though a hole in the truck and as the branch grows its cambium will grow into and fuse with the cambium of the trunk.
Here are pictures showing where the dead branch had been and the proposed new branch. Note the large space between the branches on the left side of the tree. The new branch will occupy that space.
First you strip off all of the leaves on the donor branch right down to the branch. Then you drill a hole in the trunk slightly larger than the branch.
Note that the green wood in the hole will close down. You will have to ream the hole and clean up all chips and stringers that will clog the hole. Once you have a clean hole that you can see through, you can thread the end of the branch into the hole. Be sure to have a bud on the branch just outside of the trunk.
Use cut past to seal around the new branch and the trunk – on both sides of the trunk.
In 2 years it will look like this and you can cut off the back side of the branch. Note the donor branch comes in from the left and out to the right. The right side has grown extra side branches. The left side will be removed.
