Budding
Ray R. Rothenberger and Christopher J. Starbuck
Department of Horticulture
Budding is a method of grafting in which the scion (upper portion of the graft)
is a single bud rather than a piece of stem or twig. Many of the same conditions
and materials used for other forms of grafting also apply to budding
Budding is most frequently used to multiply a variety that cannot be produced
from seed. It is a common method for producing fruit trees, roses and many
varieties of ornamental trees and shrubs. It may also be used for topworking
trees that can't be easily grafted with cleft or whip grafts. The stone fruits,
cherry, plum and peach, are examples.
Why propagate
by budding?
Budding, particularly "T" budding, is faster than any other grafting technique.
With a little practice, the right conditions and compatible plants, the percentage
of successful unions can be high. Experienced budders may get 90 to 100 percent
take. Even for the beginner, the percentage of successful unions is usually greater
than with other forms of grafting. Budding is also well adapted to plant shoots
from 1/4 to 1 inch in diameter. In larger branches, buds may be inserted in vigorously
growing twigs near the upper part of the plant.
Besides ease and success, a stronger union is formed than those made with
other grafting techniques. Because only a single bud is inserted, you can produce
a number of new plants even when scion wood of a new variety is scarce.
When is the time
to bud?
"T" budding can be done almost any time that the bark of the stock slips (easily
separates from the wood) and buds are fully developed. Most budding is done
from late July to early September (fall budding). Buds set at this time normally
remain dormant until the following spring. In cold climates, bud growth in
fall is undesirable because young shoots are subject to winter injury. Fall
budding is the most common technique for producing fruit trees. Spring budding
(in March and April) is possible but is less desirable than fall budding. Another
process called June budding is best suited to climates with relatively long
growing seasons. Beginners should select fall budding.
How should stock
be prepared?
Young plants selected for the understock must have new, vigorous growth. In
early summer, take off any shoots on the lower 6 inches of the trunk. This
gives you a smooth surface to work on. Most budding of young plants is done
2 to 3 inches above the ground; however, it is possible to bud higher.
What are budsticks?
The budstick is a twig, usually from the current season's growth. It is taken
from the plant of the desirable variety to be increased. It should have average
vigor, be healthy and have plump, well-developed buds. Buds on the center of the
twig are generally better than those near the tip or the base (where the twig
may have branched from another limb).
As soon as you cut the budstick from the tree or shrub, clip off the leaves;
allow about 1/2 inch of the leafstalk to remain as a handle. Use budsticks
as soon as they are taken from the tree, but if necessary, they may be stored
in cool, moist conditions.
How should
buds be selected and prepared?
As in other forms of grafting, a very sharp knife is important. Special budding
knives are available that can be used for making the cuts and lifting bark for
easy bud insertion. To cut a bud from the budstick, start 1/2 to 3/4 inch below
the base of the bud (Figure 1). Make a smooth, slicing cut upward that extends
1/2 to 3/4 inch above the bud. As you finish the cut, bring the knife upward to
release the bud. You must cut the wood (shield) attached to the bud straight (Figure
2). Beginners often remove buds with a slightly curved cut. A curve in the shield
(wood attached to the bud) makes poor contact and most likely will not form a
union. When you cut the bud from the budstick, you must immediately insert it
into the understock before either dries. Any drying or dirt on the bud shield
can mean failure. Some budders remove the wood from the shield, leaving only the
bark and bud for insertion. However, beginners will be more successful if they
leave the wood on the bud piece.
Figure
3
Forming a "T" cut in the stock.
How
should the understock be prepared?
The most common and successful cut made in the understock for budding is the
T cut. Select a smooth, branch-free location on the stock. Make a vertical cut
parallel with the grain of the wood by drawing the knife upward (Figure 3, left).
The cut should be about 1-1/2 inches long. Position this cut so the bud will fall
in the proper location. Remember that once inserted, the bud should be placed
in about the center of this vertical slit.
After making the vertical cut, make a cross cut which forms a T at the top
of the vertical cut (Figure 3, right). Make the cross cut at a slightly downward
angle to make insertion of the bud piece easier. Cut through the bark but not
into the wood.
Figure 4
Slide the bud into the vertical slit until the top is even with or below the cross
cut.
How is the
bud inserted?
After making the two cuts to form the T, gently lift the bark at the junction
of the two cuts with the knife. However, if the bark is slipping properly, this
step may not be necessary.
To insert the bud, place the base of the bud shield into the slit at the top
of the T cut. Slide the bud down into the vertical slit until the top of the shield
is even with or below the cross cut (Figure 4).
Leaving the 1/2 inch of leafstalk as a handle can make insertion easier. However,
with experience, buds can be inserted without it. Prompt insertion as soon as
the buds have been cut from the budstick is important.
Figure
5
Wrap the bud tightly with a budding rubber.
How should
the bud be wrapped?
After the bud has been placed in the T cut, it should be wrapped. Rubber budding
strips are common and easy to use. However, string or raffia may also be used.
You can start either above or below the bud, but generally it is better to start
above and wrap downward to keep from pushing the bud out if the bark is loose
(Figure 5). Make three or four wraps above the bud and three or four below. Finish
with a self-binding loop. Try to cover the horizontal cut of the T with one loop
of the wrap. Never cover the bud.
What care does
the young bud require?
Check the bud one week to 10 days after it has been set. By that time you should
be able to tell whether or not it has formed a union. If both the bud and the
surrounding bark of the bud shield are shriveled and dry, it has not taken. You
may have time to graft another bud on the stem. If a union has taken place, the
bud and shield will look fresh. If non-elastic wrapping materials were used, cut
them off at this time. If elastic wrapping bands were used, they may be cut at
any time. Some will deteriorate naturally in a few weeks.
In spring, after the bud starts swelling, cut off the stock near the cross
of the T. Occasionally, birds may present a problem. They may light on the developing
bud shoot and break it loose before it is completely healed. In such situations,
it is better to cut the stock off 4 to 5 inches above the bud to avoid such breakage.
This stub above the bud can be cut back later when the shoot is larger and more
durable.
As the bud begins growing, buds from the rootstock may develop shoots. They
should all be removed as soon as they appear before they are more than 2 to 3
inches long.
Do not prune the new branch that has developed from the bud during the first
summer. If there is danger of it being broken by wind, it would be better to
tie it to a stake or devise other means of support than prune it.
What is patch
budding?
Among the several budding techniques, patch budding and T budding are the most
frequently used. Patch budding is slower and more difficult than T budding, but
it is useful on thick-barked trees that can't be T budded. In Missouri, patch
budding is suitable for walnuts, pecans and their relatives.
For successful patch budding, both the bark of the understock and the budstick
must be slipping easily. This form of budding is most often done in late summer
or early fall, but you can do it in the spring as soon as the bark slips. It is
best to have the budstick and understock about the same size in diameter, although
it is possible to place a patch bud on stocks as large as 4 inches in diameter.
For a successful patch bud, it is essential that the size of the bud and
its attached bark be the same size as the patch cut on the understock. For
this reason, double-bladed knives or other special tools have been devised
to make perfectly parallel horizontal cuts. These cuts are usually about an
inch apart.
How should
the bud be prepared for patch budding?
When you prepare for patch budding in late summer, select wood for budsticks
about two to three weeks before you plan to do the budding. At that time, cut
the leaf blades from these areas. Allow the petioles to remain. Do not cut the
budsticks from the tree. By the time you plan to do the budding, the petioles
will have dropped or are easily removed, and the leaf scar will have healed over.
Cut these budsticks as needed and keep them moist and protected from direct sun
or intense heat.
To remove the bud from the budstick, use the double knife to make parallel
horizontal cuts equal distances above and below the bud. Then, make vertical
cuts about an inch apart at each end of the horizontal cuts. This makes a patch
about 1 inch square. Remove this patch from the budstick by pushing sideways.
If you pull it from the stick, you may pull out the center of the bud. If the
core of the bud stays on the budstick, the patch bud will not grow.
How should
the understock be prepared for patch budding?
A patch similar to that made for the bud must also be made in a clean, straight-grained
portion of the understock. Remove the bark from the understock and quickly
insert the patch containing the bud. Do both operations quickly, so neither
the bud nor the understock have a chance to dry out. The inserted patch should
fit snugly on all four sides. Cut the patch in the understock before the patch-bud
is removed from the budstick. It is more important that the patch fit snugly
at the top and bottom than the sides; however, a snug fit on all four sides
is best.
How should
the patch bud be wrapped?
Immediately after insertion, wrap the patch. If the bark of the understock
is thicker than that of the bud, pare it down so that the bud will not be loose
after wrapping. Don't cover the bud during wrapping, but all four cuts must be
covered. Nurserymen's adhesive tape or masking tape are sometimes used. Heavy
cotton string may also be used to hold the bud tight, but the edges of the patch
must be waxed.
Don't allow the wrapping to constrict the bud union. About 10 days after
budding, check the buds and release the wrapping by making a single vertical
cut on the back side of the understock away from the bud. Do not try to pull
off the wrapping if it sticks to the bud or understock. You only want to release
tension.
How should the
understock be cut back?
As with other forms of budding, don't cut the stock back until the bud union
is completed. When the budding is done in fall, don't cut the stock back until
growth starts in the spring. If the budding is done in the spring, cut the stock
back about 10 days after you inserted the bud and it has formed a union.
G6972, reviewed October 2002