Grafting and budding are methods of asexual plant propagation that join
plant parts so they will grow as one plant. These techniques are
used to propagate cultivars that will not root well as cuttings or
whose own root systems are inadequate. One or more new cultivars
can be added to existing fruit and nut trees by grafting or
The portion of the cultivar that is to be propagated is
called the scion. It consists of a piece of shoot with dormant
buds that will produce the stem and branches. The rootstock, or
stock, provides the new plants root system and sometimes the
lower part of the stem. The cambium is a layer of cells located
between the wood and bark of a stem from which new bark and wood
cells originate. (See Fruit chapter for discussion of apple
Four conditions must be met for grafting to be
successful: the scion and rootstock must be compatible; each must
be at the proper physiological stage; the cambial layers of the
scion and stock must meet; and the graft union must be kept moist
until the wound has healed.
Whip or Tongue Graft
Cleft grafting is often used to change the cultivar or top growth of a
shoot or a young tree (usually a seedling). It is especially
successful if done in the early spring. Collect scion wood 3/8 to
5/8 inch in diameter. Cut the limb or small tree trunk to be
reworked, perpendicular to its length. Make a 2-inch vertical cut
through the center of the previous cut. Be careful not to tear the
bark. Keep this cut wedged apart. Cut the lower end of each scion
piece into a wedge. Prepare two scion pieces 3 to 4 inches long.
Insert the scions at the outer edges of the cut in the stock. Tilt
the top of the scion slightly outward and the bottom slightly
inward to be sure the cambial layers of the scion and stock touch.
Remove the wedge propping the slit open and cover all cut surfaces
with grafting wax.
Unlike most grafting methods, bark grafting can be used on large limbs,
although these are often infected before the wound can completely
heal. Collect scion wood 3/8 to 1/2 inch in diameter when the
plant is dormant, and store the wood wrapped in moist paper in a
plastic bag in the refrigerator. Saw off the limb or trunk of the
rootstock at a right angle to itself. In the spring, when the bark
is easy to separate from the wood, make a 1/2-inch diagonal cut on
one side of the scion, and a 1-inch diagonal cut on the other
side. Leave two buds above the longer cut. Cut through the bark of
the stock, a little wider than the scion. Remove the top third of
the bark from this cut. Insert the scion with the longer cut
against the wood. Nail the graft in place with flat-headed wire
nails. Cover all wounds with grafting wax.
Whip or Tongue Grafting
This method is often used for material 1/4 to 1/2 inches in diameter. The
scion and rootstock are usually of the same diameter, but the
scion may be narrower than the stock. This strong graft heals
quickly and provides excellent cambial contact. Make one 2
1/2-inch long sloping cut at the top of the rootstock and a
matching cut on the bottom of the scion. On the cut surface, slice
downward into the stock and up into the scion so the pieces will
interlock. Fit the pieces together, then tie and wax the union.
Care of the Graft
Very little success in grafting will be obtained unless proper care is
maintained for the following year or two. If a binding material
such as strong cord or nursery tape is used on the graft, this
must be cut shortly after growth starts to prevent girdling.
Rubber budding strips have some advantages over other materials.
They expand with growth and usually do not need to be cut, as they
deteriorate and break after a short time. It is also an excellent
idea to inspect the grafts after 2 or 3 weeks to see if the wax
has cracked, and if necessary, rewax the exposed areas. After
this, the union will probably be strong enough and no more waxing
will be necessary.
Limbs of the old variety which are not selected for
grafting should be cut back at the time of grafting. The total
leaf surface of the old variety should be gradually reduced as the
new one increases until at the end of 1 or 2 years, the new
variety has completely taken over. Completely removing all the
limbs of the old variety at the time of grafting increases the
shock to the tree and causes excessive suckering. Also, the scions
may grow too fast, making them susceptible to wind damage.
Budding, or bud grafting, is the union of one bud and a small piece of
bark from the scion with a rootstock. It is especially useful when
scion material is limited. It is also faster and forms a stronger
union than grafting.
Plants with thick bark should be patch budded. This is done while the
plants are actively growing, so their bark slips easily. Remove a
rectangular piece of bark from the rootstock. Cover this wound
with a bud and matching piece of bark from the scion. If the
rootstocks bark is thicker than that of the scion, pare it
down to meet the thinner bark so that when the union is wrapped
the patch will be held firmly in place.
This budding method can be used when the bark is not slipping. Slice
downward into the rootstock at a 45o angle through 1/4
of the wood. Make a second cut upward from the first cut, about
one inch. Remove a bud and attending chip of bark and wood from
the scion shaped so that it fits the rootstock wound. Fit the bud
chip to the stock and wrap the union.
This is the most commonly used budding technique. When the bark is
slipping, make a vertical cut (same axis as the root stock)
through the bark of the rootstock, avoiding any buds on the stock.
Make a horizontal cut at the top of the vertical cut (in a T
shape) and loosen the bark by twisting the knife at the
intersection. Remove a shield-shaped piece of the scion, including
a bud, bark, and a thin section of wood. Push the shield under the
loosened stock bark. Wrap the union, leaving the bud exposed.
Care of Buds
Place the bud in the stock in August. Force the bud to develop the
following spring by cutting the stock off 3 to 4 inches above the
bud. The new shoot may be tied to the resulting stub to prevent
damage from the wind. After the shoot has made a strong union with
the stock, cut the stub off close to the budded area.
Plant Tissue Culture for the Home
Although technical procedures for aseptic culture of plant cells,
tissues, and organs are as diverse as the plant material on which
they are practiced, a simplified general procedure can be followed
in the home. All that is needed are a few basic supplies which can
easily be obtained. The procedures outlined in this section can be
used in the home to propagate various species of plants, both easy
(African violets, coleus, chrysanthemums) and difficult (orchids,
ferns, weeping figs) to propagate.
For 2 pints of tissue culture medium, mix the following ingredients in a
1-quart home canning jar:
- 1/8 cup sugar
1 teaspoon all-purpose, soluble fertilizer mixture. Check the label to
make sure it has all of the major and minor elements,
especially ammonium nitrate. If the latter is lacking, add 1/3
tsp. of a 35-0-0 soluble fertilizer
- 1 tablet (100 mg) of inositol (myo-inositol) which can be
obtained at most health food stores 1/4 of a pulverized
vitamin tablet which has 1 to 2 mg of thiamine
- 4 Tablespoons coconut milk (cytokinin source) drained from
a fresh coconut. The remainder can be frozen and used later.
- 3 to 4 grains (1/400 teaspoon) of a commercial rooting
compound which has 0.1 active ingredient IBA
Fill the jar with distilled or deionized water. If
purified water is not available, water that has been boiled for
several minutes can be substituted. Shake the mixture and make
sure all materials have dissolved.
Baby food jars with lids, or other heat-resistant glass
receptacles with lids can be used as individual culture jars. They
should be half filled with cotton or paper to support the plant
material. The medium should be poured into each culture bottle to
the point where the support material is just above the solution.
When all bottles contain the medium and have the lids
loosely screwed on, they are ready to be sterilized. This can be
done by placing them in a pressure cooker and sterilizing them
under pressure for 30 minutes or placing them in an oven at 320oF
for 4 hours. After removing them from the sterilizer, place them
in a clean area and allow the medium to cool. If the bottles will
not be used for several days, wrap groups of culture bottles in
foil before sterilizing and then sterilize the whole package. Then
the bottles can be removed and cooled without removing the foil
cover. Sterilized water, tweezers, and razor blades, which will be
needed later, can be prepared in the same manner.
Plant Disinfection and Culture
Once the growing medium is sterilized and cooled, plant material can be
prepared for culture. Because plants usually harbor bacterial and
fungal spores, they must be cleaned (disinfected) before placement
on the sterile medium. Otherwise, bacteria and fungi may grow
faster than the plants and dominate the culture.
Various plant parts can be cultured, but small,
actively growing portions usually result in the most vigorous
plantlets. For example, ferns are most readily propagated by using
only 1/2 inch of the tip of a rhizome. For other species, 1/2 to 1
inch of the shoot tip is sufficient. Remove leaves attached to the
tip and discard. Place the plant part into a solution of 1 part
commercial bleach to 9 parts water for 8 to 10 minutes. Submerge
all plant tissue in the bleach solution. After this time period,
rinse off excess bleach by dropping the plant part into sterile
water. Remember, once the plant material has been in the bleach,
it has been disinfected and should only be touched with sterile
After the plant material has been rinsed, remove any
bleach-damaged tissue with a sterile razor blade. Then remove the
cap of a culture bottle containing sterile medium, place the plant
part onto the support material in the bottle making sure that it
is not completely submerged in the medium, and recap quickly.
Transferring should be done as quickly as possible in a
clean environment. Therefore, scrub hands and counter tops with
soap and water just before beginning to disinfest plant material.
Rubbing alcohol or a dilute bleach solution can be used to wipe
down the working surface.
After all plants have been cultured, place them in a
warm, well-lit (no direct sunlight) environment to encourage
growth. If contamination of the medium has occurred, it should be
obvious within 3 to 4 days. Remove and wash contaminated culture
bottles as quickly as possible to prevent the spread to
When plantlets have grown to sufficient size,
transplant them into soil. Handle as gently as possible because
the plants are leaving a warm, humid environment for a cool, dry
one. After transplanting, water the plants thoroughly and place
them in a clear plastic bag for several days. Gradually remove the
bag to acclimate the plants to their new environment; start with
one hour per day and gradually increase time out of the bag over a
two-week period until the plants are strong enough to dispense
with the bag altogether.