Chip budding
is used in situations where T-budding might also be appropriate, especially
in the nursery production of temperate fruit trees (apple, cherry), and some
ornamental shade trees (honeylocust, maple, etc.). The advantage of chip budding
over T-budding is that the bark need not be slipping for the operation to be
performed successfully, hence it can be performed slightly later in the fall
budding season. Also, chip bud union formation is faster and stronger. However,
with chip budding it is necessary to be more careful to get good alignment of
the stock and scion cambia.. For information about the use and commercial applications
of Chip Budding, including links to several Web sites which describe it in detail,
go to Chip Budding under
the List of Grafting
and Budding Methods.
- Choose a hibiscus stock plant with a stem diameter of at
least 0.5 cm, but not
greater than 1.0 cm at the point at which you intend to place the
scion bud.
- A chip (or T-bud) should be placed at a point on the stem of the stock
plant that is more or less completely lignified, as indicated by a completely
formed a bark (brown), rather than a terminal soft green stem.
- The chip (or T-) bud can be placed at any height up from the base, to build
a multi scion scaffolded tree.
- Inserting more than two buds (Chip and/or T-) is not recommended, to minimize
competition for resources and avoid prolonged bud dormancy.
2. Cutting the stock plant
After reading through the following steps, insert your CD into the CD-drive and
find the file called "". Click it to view
the video. You may want
to drag the movie window around to appropriate place so that you can see the text and
movie at the same time.
- Using pruning shears or grafting knife, remove larger leaves and flowers
from the portion of the shoot where you plan to place the scion.
- Before cutting, note the shape of the internode piece you will remove from
the stock plant, and the complementary bud piece you will replace it with
from the scion donor plant. The should be as nearly identical as possible.
Note that the "vertical"
and "horizontal" cuts are made at an angle - approximately
20o from the vertical in the case of the former and approx. 45o
from vertical in the case of the latter. In some cases the "vertical"
cut is more or less straight, as shown in the previous image, but more typically
it is curved
downwards.
- Make the first
cut approx. 1.5 to 2.5 cm long, at an internode, by drawing the
knife through the bark and into the wood, from the top downwards (approx.
20o angle). Be careful that the lower end of this cut does
not extend to far inward toward the center of the stem. It should not extend
inward more that about half the diameter of the stem (i.e. to the center of
the stem), to avoid accidentally breaking the stem off at that point later
on.
- Begin the second
cut slightly (2 to 3 mm) below the bottom end of the first cut,
drawing the knife downwards at an approx. 45o angle, until
it intersects the bottom of the first cut. The more or less triangular piece
of bark and wood can be easily removed from the stock, to create a space for
the scion bud chip. Note that the bottom "shelf"
of this new space is not flat, but at an approximately 45o
angle, so the new scion bud is less likely to drop out before tying.
3. Cutting and inserting the scion bud
After reading through the following steps, insert your CD into the CD-drive and
find the file called "". Click it to view
the video. You may want
to drag the movie window around to appropriate place so that you can see the text and
movie at the same time.
- Scion selection: In the case of temperate fruit trees, select
a well developed, vegetative or mixed (apple) bud at least several nodes down
from the terminal end of the branch from the scion donor tree. For fall budding
of fruit trees this bud should be should be dormant but not yet defoliated.
The scion buds should be from a woody section of stem, not a green, unharded,
actively growing tip. In the case of tropical hibiscus, which does not for
a discrete dormant bud, choose a node where there is little if any lateral
shoot growth.
- For field budding of fruit trees, bud sticks with several suitable buds
are collected from scion donor plants several hours earlier (preferably in
the morning). Leaves are removed, retaining a 5 to 10 mm long petiole stump.
This minimize transpirational water loss from bud stick. They are stored
under cool, dark conditions. E.g. wrapped in damp burlap and kept in an insulated
container out of the sun. In the case of hibiscus, cut and insert your
bud piece immediately after removing a complementary section from the stock.
- Using the same two cuts as described above for the stock, cut a bud piece
out that as nearly identical
in shape and size as possible to the piece removed from the stock.
If necessary, it may be slightly smaller in diameter, but not larger.
- Using the petiole stump of the scion bud as a "handle", place it into the
complementary space in the stock. If properly cut, the cut surfaces should
be in full contact with each other along both cuts. If the scion bud chip
is the same diameter as the internode piece removed from the stock, the cambia
of stock and scion should be perfectly aligned. If the bud chip is smaller
than the space it will fit into, it should not be centered, but rather
placed over to one side so the cambia line up on at least one side.
4. Tying the bud
After reading through the following steps, insert your CD into the CD-drive and
find the file called "". Click it to view the video. You may want
to drag the movie window around to appropriate place so that you can see the text and
movie at the same time.
- The budding
rubber is wrapped tightly (pressure) around the stock and the new
scion bud, from the bottom upwards, so that the edges
of the budding rubber overlap like shingles on a roof. This
helps avoid accumulation and entry of rain water through the cracks. Begin
tying a few millimeters below the bottom of the bud. Trap the bottom
end of the budding rubber beneath the first turn by holding the end at an
ascending angle with the thumb and forefinger of your left hand while simultaneously
stretching and wrapping the band in a counter clockwise direction, creating
an "X". Continue turning, overlapping each turn by about half the
diameter of the budding rubber. Go around
rather than over the bud itself, or small lateral shoot in the
case of hibiscus, continuing up about 1 cm above the bud. In some cases
with apple and other fruit trees, if the bud is small and hard, it may be
completely
covered by the budding rubber.
- Terminate the wrapping about 1 cm above the top of the new bud chip by
pulling
out a "loop" with the right ,hand tucking the end of the rubber band
through this loop, and then pulling
the end through, before releasing it and trapping it in place.
- Although fruit tree chip buds are not wrapped further, in the case of hibiscus,
you may wish to cover the first (rubber) wrapping with a piece of parafilm
to further minimize moisture loss. Cut a piece
of parafilm about two inches wide and 3 inches long. The paper
backing is divided into two inch sections, so cut it along that line. Remove
the paper backing, and fold this 2 x 3 inch piece in half long ways so it
measures about 1 x 3 inches. To adhere firmly, the parafilm should be stretched
slightly before it is wrapped in place. Hold one end of the parafilm just
below the bottom end of the budding rubber wrapping, and wrap upwards, just
as you did with the budding rubber, until the rubber wrapping is entirely
covered. Remember to stretch the parafilm as you wrap. At the upper end, fix
the parafilm in place, so it will not unwrap, by running your thumbnail across
it, to create a crease, which tends to stick it to the layer of parafilm below.
- For large scale field budding of fruit trees, tying is often done by a
second person following directly behind the budder. A team
like this can do a thousand or more buds a day.
5. Post budding management of the Chip budded plant
- Place the budded hibiscus under shade in the greenhouse for two to
three weeks, before removing the tying materials and inspecting the
graft. A thin line of whitish callus along the cut edge is a good sign that
the stock and scion are beginning to form a graft union. Replace the wrapping
material for several more weeks.
- If you have not grafted another scion onto the terminal end of the same
shoot where one or two bud grafts have been placed, shoot growth from the
new bud can be encouraged by cutting back the top of the shoot to remove apical
dominance. If this is not feasible shoot growth may be delayed for many weeks,
even though the graft union is completely healed.