Thread Grafting New Roots onto Bonsai

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Thread Grafting New Roots onto Bonsai

The seedling will be encouraged to grow strongly this year; the greater its growth, the faster the graft will take.

When the seedling and the main tree have visibly joined and healed together, the upper part of the seedling will be gradually pruned down until all that is left are its roots growing into the main tree.

Patience is necessary; at the very earliest this separation will take place in a years time.

Hawthorn threadgraft

The main tree and the threadgraft July 2005

Hawthorn rootgraft

Update: December 2006. By August of this year, the threadgrafted shoot had grafted tightly into position. The top section of the threadgrafted seedling was pruned away leaving its base as part of the main tree.

Hawthorn rootgraft

The Hawthorn bonsai itself; December 2006

Another example of threadgrafting roots; this time on an Acer campestre/Field Maple.

Acer campestre/Field Maple

Acer campestre, as with most Acer species, exhibit strong root growth. Though there are three strong lateral/surface roots that are being to develop some division and taper; there are also two large gaps in between these three surface roots.

With many maples, new roots could be encouraged by simply scoring the bark of the trunk, however, if new roots were to emerge, they would require many years of strong growth to thicken as much as the three existing surface roots.

Instead, three young, pencil-thick Acer campestre saplings are thread-grafted into the gaps in the nebari. These will take much less time to become nearly as thick as the existing surface roots.

Acer campestre/Field Maple

In this image the three saplings (new roots) have been threadgrafted into position.

A couple of reed-sticks have been lodged across the roots to ensure the new roots keep their positions when they are covered back over with soil.

Notice that the exisiting larger roots have been pruned to ensure a smooth transition into the smaller secondary surface roots; just as you would ensure a smooth transition between the branch sections of a bonsai.

Acer campestre/Field Maple

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