(VA101)
Suppose you have a tree with branches on only one side, or a bonsai with
too few branches, or a lopsided espalier. Using conventional grafting methods,
you would have a hard time dealing with these problems, but the Veritas®
Plugger® and a common pencil sharpener can provide a quick solution to
the difficulties.
The Plugger is nothing more than a cone-shaped bit with a 16° taper (the
same taper as a standard pencil sharpener). This allows for a perfect fit
between a hole tapered with the Plugger and a scion (the part to be grafted,
usually a small branch) sharpened in a pencil sharpener. It also allows you
to put branches anywhere you wish.
Note: The Plugger grafting bit can only taper an existing hole
to the proper shape. It will not drill. This bit is to be used in conjunction
with a 1/8" drill bit. Use the drill bit to make the hole to the proper
depth and then use the Plugger to taper the hole to the proper shape.
About Cambial Contact
Figure 1: To ensure a successful graft, it is important to allow for as much
cambial contact as possible. The amount of contact shown is sufficient for
a strong join.
Figure 2: Sharpening the branch.
Figure 3: Tapering the hole.
Figure 4: Placing the branch in the hole.
Figure 5: Applying wound dressing.
Figure 6: Grafting double leaders.
The cambium is the thin layer of green between the inner bark and the sapwood.
As the cambium grows, the cells divide, producing bark on the outside, and
sapwood on the inside of the tree. The cambium is also the source of a tree's
annual rings. Both the scion and the host plant must be from the same genus,
although dissimilar (but related) genera, such as quince and pear, will sometimes
join.
A successful graft requires close and firm contact between the cambium layers
of the scion and the host plant (see Figure 1). Take care to insert
the basal end (the end that was pointing towards the trunk or roots on the
donor plant) into the host plant; otherwise, the graft won't work.
To make a graft using the Plugger, proceed as follows:
- Take a pencil-thick section of scion and sharpen the basal end using a
pencil sharpener. Try our Giant Pencil Sharpener (99K88.01), if you don't
already have one.
Note: Always clean the blades of the pencil sharpener after you
have used it in conjunction with the Plugger, as green wood will tend to clog
the cutters.
- With a 1/8" drill, drill a hole 1/2" deep into the branch or
trunk that you wish to graft on. A deeper or shallower hole may be necessary,
depending on the size of the scion and the thickness of the trunk. Drill
into the trunk at a 90° angle, then taper the hole with the Plugger
(VA101). Test the scion in the hole from time to time and stop drilling/tapering
when a close fit is achieved.
- Insert the scion into the tapered hole. There should be a snug fit, and
the cambium layers should line up as closely as possible. If you can't get
a close fit, try sharpening the scion again. Only redrill the hole if it
is too shallow to allow the cambia to match. To prevent the scion from drying
out, the two areas of sapwood must be in contact.
- Once the scion has been inserted, you should cover the join with grafting
wax or latex-based tree wound dressing. This will retain the moisture necessary
for a successful join.
This grafting method may also be used to create a natural brace for weak
branches. Many trees that are not regularly pruned develop weak crotches,
especially between double leaders. As the tree grows in size, the weight of
these limbs increases, and they become dangerous during wind or ice storms.
If the tree is still young, a natural brace can be made by joining these limbs
with a scion. In this case the orientation of the basal end is of no consequence,
as the tree will adjust for it (e.g., if the basal end is placed in the left
leader, the sapwood will conduct toward the right leader and the inner bark
will conduct towards the left leader. If the placement is reversed, the opposite
will happen). It is good practice to insert the scion with bow in it, thereby
giving it extra slack. This will allow the two branches to bend and sway toward
and away from each other without pulling the scion out. Once the grafts take,
the scion will provide a strong brace, with a more natural appearance than
cables or threaded rods.
Tip:
While the grafts take, it is best to keep the join stable by lashing the branches
together with rubber tubing.
IWE-074 Rev. A