Thread Grafting

Thread grafting is ideal for creating branches or roots at the precise point where they are needed to complete or improve the design.

The technique itself couldn’t be simpler.

Grafting branches 

Grafting can be done any time between early spring and mid-summer, and will take between one and three years to work, depending on the vigour of the tree.

First you need to allow some shoots to grow freely until they are long enough to be bent around to cross the trunk at the point where the new branch is needed or alternatively use a sapling which can remain in its pot beside the recipient.
Then you drill a hole straight through the trunk at the point where the branch is to be grafted. Start at the side where you want the branch is to emerge (this ensures the cleanest edge to the hole on that side of the trunk)

Take a convenient shoot and carefully CUT off all the leaves very close to the shoot. Don’t pull them off or you will damage the axillary buds.

Bend the shoot and push it through the hole as far as it will go without breaking or until it makes a tight fit.
Tape or wire the shoot into place, seal the edges of the wound and wait….
… When the shoot, or new branch, becomes much thicker on the side it emerges than on the side where it enters the trunk, it is a sign that the graft has “taken”.

Wait one more year before severing the branch on the insertion side – just to be on the safe side. If the shoot is on its own roots in a pot, this must be watered and fed as usual.
That’s really all there is to it. As the shoot thickens and the wound begins to heal, the two are forced together with such pressure that a natural graft occurs. There’s no need to expose the cambium on the inserted shoot or to get up to any other fancy tricks – just let nature take its course.

Be very careful when wiring new grafts because, remember, they are only held in place by a very thin layer of new tissue and will easily come away. As time passes they will become much more robust.

Grafting roots

The principle of thread grafting new roots is precisely the same as for branches, except that when the graft has taken, you retain the “parent” part, and discard the other. Best time for this operation is early spring, before the buds open, but it can be done with care any time during spring/early summer.

Find a healthy seedling of the same or closely similar variety as the main tree. The stem of the seedling must be roughly the same thickness as the existing surface roots on the main tree.

Drill the hole at an angle sloping upward from the exact point where you require the new root.
Excavate a wedge of soil in the pot to accommodate the roots of the seedling.

Prune all lateral branches and leaves off the seedling and push it up through the hole, making as tight a fit as possible.
Gently arrange the roots in the excavated space and refill with soil. Water thoroughly and keep the assembly in the shade for a few weeks.
Feed the tree well to encourage rapid thickening of the inserted stem and healing of the wound.
Always wait a season longer than you think is necessary before cutting off the free-growing top of the inserted stem, leaving the trunk base and roots behind.