GRAFTING FRUIT TREES
To accompany this article there
are two Fact-sheets that I've compiled which are available for you to
Trees - Rootstock Guide
Trees - Pollination Guide
I was fascinated
by grafting when I was a boy at Tregaron County School, and got taught
the basic (?black art?) theory about such things by dear old Mr
Lewis - in what was called "Rural Science Studies" (RSS) in those days.
Mr Lewis was an
unassuming ex RAF Spitfire pilot and one of the nicest and most
genuinely humble teachers that I've ever had the pleasure to meet.
mostly involved horticultural studies and we got a taste of it for one
double lesson once a week. It was one of those early post war subject
that was taught to all children in order to heighten everyone's
knowledge about growing food - in case we experienced another war I
presume! The school even had a big vegetable garden with a high chain
link fence around it - so that we could practice in the day but not
return later to take our efforts home to Mam!
later got dropped from the curriculum, after all the fears that had
sprung up from WW2 food shortages had calmed down and the panic had
subsided (about 25 years after the end of that particular war in 1945!).
Personally I think
they should bring it back for our children in this modern world we now
live in - (RSS that is - not war!). It was one of the best - and, for
me, one of the most interesting & practical subjects possible for
youngsters. Not only should RSS be brought back, but along with it
wood-work and domestic science (cooking & needle-work). The governments
since the war, in my view, should also have perpetuated the "Dig for
Victory" campaign (not that I can remember that one myself - being a
product of the early 50s!). They should have kept it and called it
something else more sexy, like "survival post capital collapse!".
Perhaps "sexy" is not the word I'm looking for there!
I was totally
engrossed in the techniques and methods of making one plant grow from
another (perhaps it's due to the Dr Frankenstein that lurks inside most
of us - especially when we were young boys). More especially the
thought of being able to grow different varieties of apples on the same
tree was even more intriguing!
I always used to
come close to, if not top of the class in RSS during most school terms
- perhaps that's where I should have concentrated my efforts, rather
than becoming an electronics engineer as a professional first, and an
amateur vegetable gardener on an allotment plot second. I dropped RSS
somewhere along my educational journey through school - in preference
for the more academic subject of Physics & some other more "modern"
science offerings. However the old school's textbook diagrams of "Whip &
Tongue" & "Saddle" grafts have stayed with me as an image in my memory
to this day.
Few of us get a
lot of opportunity to do fruit tree grafting on a regular basis - unless
you happen own an orchard. Or if you hire yourself out as a professional
grafter to more timid fruit tree growers, who subscribe to the old myth
that grafting is a complicated and ticklish procedure, that can only be
accomplished by someone with the intellect & the steady hand of a brain
surgeon (hence why I called it a "black art" above). In reality nothing
is further from the truth! It's not a "black" art at all. Grafting your
own trees is very easy once you know the basics. The science behind
grafting however is fascinating.
A good question to
which there is a VERY simple answer!
To those gardeners
amongst us who are used to starting all their crops from seed, it may
come as a surprise to learn that fruit trees are NOT grown from seeds
(or pips as they are called) but are, in fact, grafted.
This may seem a very unnatural concept, but there's a very good reason
for it - and the answer again goes back to your school biology lessons.
Like us humans,
the pips (or stones) produced by a fruit tree are unique to that
particular tree, it is the only one of it's kind in the world and it's
characteristics are a random mix of it's parents' genes. Exactly like us
humans. The embryos produced that eventually grow into adult humans by
two parents will always be unique. So you could have a fantastic new
variety of apple created from a tree grown from a pip, or you could land
up with something which is totally useless. In other words it's a
A fruit tree
supplied from a nursery consists of two parts, the
scion (the fruiting wood) which makes up most of the tree
that you see above ground-level, and the rootstock
which - as the name suggests - is the root & lower trunk. The join or
"union" is easy to spot in a young tree - it is the kink a few inches
above the ground where the scion was grafted on to the rootstock.
works because rootstocks are very closely related to scions - thus apple
rootstocks are apple varieties in their own right, but where the main
attribute is not fruit flavour but the overall vigour and eventual tree
size. Plum rootstocks can also be used for apricots and peaches, which
shows just how closely these species are related. Most rootstocks will
produce edible fruit if left to grow naturally, but the fruit is usually
small and poorly flavoured.
To guarantee the
outcome of your fruit producing tree, a length of scion wood is grafted
on to a rootstock. The scion has been cut from a known variety. You are
in effect cloning the original and implanting it on to a donor tree. The
result is you have a tree that will produce the exact fruit you
expected, but it grows on it's "surrogate mother" -the rootstock that it
was originally grafted on to! You can even graft more than one variety
on to the same rootstock - how cool is that?
This process is
really cloning at horticultural level, and it's been going
on for a LONG time Grafting with detached scions has been practiced for
thousands of years. It was in use by the Chinese before 2000 BC, and
then spread to the rest of Eurasia. The practice was almost commonplace
in ancient Greece. Without the development of grafting, heterosexual
fruit trees such as apples and cherries would never have been
domesticated, as their natural sexual reproductive method prevents
useful genes from being passed on consistently.
amazing? I certainly think so! Anyway let's get down to the nitty gritty
of this "black art"!
An Introduction to Grafting
apple trees are produced by grafting the required variety (the "scion")
on to a rootstock. The main reason for doing this is because the natural
vigour (from low to high) of the rootstock helps to control the size of
the mature apple tree. However rootstocks also confer other advantages
following table lists apple rootstocks in ascending order (1 - 5 with
five being the most vigorous) giving an approximate indication of what
the expected size of the mature apple tree would be.
Types & Habits
10ft / 3m
18ft / 5m
The most widely-used
rootstock in Europe in the 19th century was called Paradise.
During the 1920s researchers at East Malling Research
Station in the UK were the first to classify rootstocks and
develop new ones for specific purposes. One of their first
rootstocks was "M9", which was developed from Paradise and
another variety called "Jaune de Metz". (It is possible that
"Jaune" refers to the golden yellow bark of this rootstock).
Apple trees grown on M9 rootstocks are small, and they fruit
very early in life - making this an ideal rootstock for
commercial apple orchards, and it is indeed probably the
most widely-planted of all rootstocks. East Malling Research
Station, in conjunction with some other UK research stations
at Merton and Long Ashton developed a range of virus-free
rootstocks of which M27, M9, M26, MM106, M7, MM111, and M25
are in widespread use today. Note that the numbers in the
East Malling series have no relation to the size of the tree
- M27 and M26 produce trees which are respectively smaller
and larger than M9!
The table above should not be taken too
The ultimate size of a fruit tree - its mature height
and spread - is affected by many characteristics. Local climate, soil
conditions, and the species (apple, plum, cherry and so on) all play a
part. Within species some varieties naturally tend to grow more
vigorously than others. Bramley's Seedling apple trees for example tend
to be bigger and stronger than Rubinette apple trees. However the most
significant factor in the ultimate size of your fruit tree is its
Furthermore, although we have created
discrete size bands for convenience, in practice the performance of
different rootstocks overlaps considerably.
(which I'll focus on in another news-letter some time in the future)
which can be performed before or during the growing season, most
grafting is done during winter and early spring while both scion and
rootstock are still dormant (by the time you get this newsletter it will
probably be a little late to do it this year). Containerized plants may
be moved indoors during the actual grafting process; after grafting,
these plants are placed in protected areas or in unheated over-wintering
houses. Field-grown stock, of course, must be grafted in place. Some
deciduous trees are commonly grafted as bare rootstock during the winter
and stored until spring planting. Indoor winter grafting is often
referred to as bench grafting because it is accomplished at a bench.
and Handling Scion Wood
The best quality
scion wood usually comes from shoots grown the previous season. Select
short lengths about the diameter (and about the length) of a pencil. In
some areas the collected scion wood is often called “pencils” for this
reason. Scions should be severed with sharp, clean shears or knives and
placed immediately in moistened burlap or plastic bags. It is good
practice during the harvesting of scions and the making of grafts to
clean the cutting tools regularly. This may be done by flaming or
immersing them in a sterilizing solution. Isopropyl (rubbing) alcohol
also works well as a sterilent, although it evaporates quite readily. An
alternative sterilizing solution may be prepared by mixing one part
household bleach with nine parts water (by volume). However, this bleach
solution can be highly corrosive to certain metals. Another sterilizing
fluid that can be used, and which is easily available is Mentholated
For best results,
harvest only as much scion wood as can be used for grafting during the
same day. Select only healthy scion wood that is free from insect,
disease, or winter damage. Be sure the stock plants are of good quality,
healthy, and true to type. Scion wood that is frozen at harvest often
knits more slowly and in lower percentage. If large quantities of scion
wood must be harvested at one time, follow these steps:
scions to a uniform length,
basal ends together, and tie them in bundles of known quantity (for
example, 20 scions per bundle).
recording the cultivar, date of harvest, and location of the stock
base of the bundles in moistened burlap or sphagnum, place them in
polyethylene or waterproof paper bags, and seal the bags.
bundles for short periods, if necessary, either iced down in
insulated coolers or in a fridge at 0o – 1o C
(32o to 34o F)
scions in refrigerated units where fruits or vegetables are
currently kept or have been stored recently. Stored fruits and
vegetables release ethylene gas, which can cause woody plant buds to
abort, making the scions useless.
Keep the scions from
freezing during storage.
In grafting, as well as budding, the vascular cambium of the scion or
bud must be aligned with the vascular cambium of rootstock. In woody
plants the cambium is a very thin ribbon of actively dividing cells
located just below the bark. The cambium produces conductive tissue for
the actively growing plant (Figure 1). This vascular cambium initiates
callus tissue at the graft and bud unions in addition to stimulating
tissue growth on the basal ends of many vegetative cuttings before they
Figure 1. Cross
section of a woody plant stem.
choose from a number of different types of grafts. This section
describes only those basic types of grafts used on nursery crop plants.
One of the
simplest and most popular forms of grafting, cleft grafting (Figure 2),
is a method for top working both flowering and fruiting trees (apples,
cherries, pears, and peaches) in order to change varieties. Cleft
grafting is also used to propagate varieties of camellias that are
difficult to root. This type of grafting is usually done during the
winter and early spring while both scion and rootstock are still
dormant. Cleft grafting may be performed on main stems or on lateral or
The rootstock used
for cleft grafting should range from 1 to 4 inches in diameter and
should be straight grained. The scion should be about 1/4 inch in
diameter, straight, and long enough to have at least three buds. Scions
that are between 6 and 8 inches long are usually the easiest to use.
Figure 2. Cleft
The stock should
be sawed off with a clean, smooth cut perpendicular to the main axis of
the stem to be grafted. Using a clefting tool wedge and a mallet, make a
split or "cleft" through the centre of the stock and down 2 to 3 inches.
Remove the clefting tool wedge and drive the pick end of the tool into
the centre of the newly made cleft so that the stock can be held open
while inserting the scion.
In cleft grafting,
one scion is usually inserted at each end of the cleft, so prepare two
scions for each graft. Select scions that have three or four good buds.
Using a sharp, clean grafting knife, start near the base of the lowest
bud and make two opposing smooth-tapered cuts 1 to 2 inches long toward
the basal end of the scion. Cut the side with the lowest bud slightly
thicker than the opposite side. Be sure the basal end of the scion
gradually tapers off along both sides.
Insert a scion on
each end of the cleft, with the wider side of the wedge facing outward.
The cambium of each scion should contact the cambium of the rootstock.
clefting tool from the cleft so that the rootstock can close. Pressure
from the rootstock will hold the scions in place. Thoroughly seal all
cut surfaces with grafting wax or grafting paint to keep out water and
prevent drying. If both scions in the cleft "take," one will usually
grow more rapidly than the other. After the first growing season, choose
the stronger scion and prune out the weaker.
temperature of grafting wax is critical. It must be hot enough to flow
but not so hot as to kill plant tissue. Recently, paint-like sealants
have replaced wax in many areas because they are easier to use and
require no heating.
Rind or Bark Graft
(Figure 3) is used primarily to top work flowering and fruiting trees.
In contrast to cleft grafting, this technique can be applied to
rootstock of larger diameter (4 to 12 inches) and is done during early
spring when the bark slips easily from the wood but before major sap
flow. The rootstock is severed with a sharp saw, leaving a clean cut as
with cleft grafting.
Figure 3. Bark graft.
Start at the cut surface of the rootstock
and make a vertical slit through the bark where each scion can be
inserted (2 inches long and spaced 1 inch apart).
scions are usually inserted around the cut surface of the rootstock,
prepare several scions for each graft. Cut the base of each scion to a 1
½- to 2-inch tapered wedge on one side only.
Loosen the bark
slightly and insert the scion so that the wedge-shaped tapered surface
of the scion is against the exposed wood under the flap of bark. Push
the scion firmly down into place behind the flap of bark, replace the
bark flap, and nail the scion in place by driving one or two wire brads
through the bark and scion into the rootstock. Insert a scion every 3 to
4 inches around the cut perimeter of the rootstock.
Seal all exposed
surfaces with grafting wax or grafting paint. Once the scions have begun
to grow, leave only the most vigorous one on each stub; prune out all
the others. Bark grafts tend to form weak unions and therefore usually
require staking or support during the first few years.
At one time the
side-veneer graft (Figure 4) was a popular technique for grafting
varieties of camellias and rhododendrons that are difficult to root.
Currently, it is the most popular way to graft conifers, especially
those having a compact or dwarf form. Side-veneer grafting is usually
done on potted rootstock.
Fig. 4 Side veneer
Rootstock is grown
in pots the season before grafting, allowed to go dormant, and then
stored as with other container nursery stock. After exposure to cold
weather for at least six weeks, the rootstock is brought into a cool
greenhouse for a few days before grafting takes place to encourage
renewed root growth. The plant should not be watered at this time.
Make a shallow
downward cut about 3/4 inch to 1 inch long at the base of the stem on
the potted rootstock to expose a flap of bark with some wood still
attached. Make an inward cut at the base so that the flap of bark and
wood can be removed from the rootstock.
Choose a scion
with a diameter the same as or slightly smaller than the rootstock. Make
a sloping cut 3/4 to 1 inch long at the base of the scion. (Use the bark
grafting technique shown in Figure 3.)
cut surface of the scion against the cut surface of the rootstock. Be
certain that the cambia contact each other.
Hold the scion in place using a rubber
grafting strip, tape, or grafting twine. Seal the entire graft area with
warm grafting wax or grafting paint. Remove the rubber or twine shortly
after the union has healed. Never allow the binding material to girdle
(Figure 5) is used to join a scion onto the stem of a rootstock or onto
an intact root-piece. This simple method is usually applied to
herbaceous materials that callus or "knit" easily, or it is used on
plants with a stem diameter of 1/2 inch or less. In splice grafting,
both the stock and scion must be of the same diameter.
Figure 5. Splice
the Stock and Scion.
Cut off the
rootstock using a diagonal cut 3/4 to 1 inch long. Make the same type of
cut at the base of the scion.
Fit the scion to
the stock. Wrap this junction securely with a rubber grafting strip or
Seal the junction
with grafting wax or grafting paint. Water rootstock sparingly until the
graft knits. Over watering may cause sap to "drown" the scion. Be sure
to remove the twine or strip as soon as the graft has healed.
Whip and Tongue
The whip and
tongue technique (Figure 6) is most commonly used to graft nursery crops
or woody ornamentals. Both the rootstock and scion should be of equal
size and preferably no more than 1/2 inch in diameter. The technique is
similar to splice grafting except that the whip on the rootstock holds
the tongue of the scion in place (and vice versa). This leaves both
hands free to wrap the joint.
For the whip and
tongue graft, make similar cuts on both the stock and scion. These cuts
should be made with a single draw of the knife and should have a smooth
surface so that the two can develop a good graft union. Up to this
point, rootstock and scion are cut the same as for a splice graft.
Figure 6. Whip and
the Stock and Scion.
Cut off the stock
using a diagonal cut. The cut should be four to five times longer than
the diameter of the stock to be grafted. Make the same kind of cut at
the base of the scion.
Next, place the
blade of the knife across the cut end of the stock, halfway between the
bark and pith (on the upper part of the cut surface). Use a single knife
stroke to draw the blade down at an angle through the wood and pith.
Stop at the base of the initial diagonal cut. This second cut must not
follow the grain of the wood but should run parallel to the first cut.
Prepare the scion
in the same way. Fit the scion into the rootstock so that they interlock
whip and tongue. Be certain that the cambia are aligned.
Wrap the junction
with a grafting strip or twine, and seal it with grafting wax or
grafting paint. Never allow the binding material to girdle the stem.
(Figure 7) is a relatively easy technique to learn and once mastered can
be performed quite rapidly. The stock may be either field-grown or
potted. Both rootstock and scion should be the same diameter. For best
results, use saddle grafting on dormant stock in mid- to late winter.
Stock should not be more than 1 inch in diameter.
Figure 7. Saddle
Using two opposing
upward strokes of the grafting knife, sever the top from the rootstock.
The resulting cut should resemble an inverted V, with the surface of the
cuts ranging from 1/2 to 1 inch long.
Now reverse the
technique to prepare the base of the scion. These cuts on the rootstock
and scion must be the same length and have the same slope so that a
maximum amount of cambial tissue will make contact when the two halves
V-notched scion onto the saddle of the rootstock. If rootstock and scion
are the same diameter, cambial alignment is easier; otherwise adjust as
Wrap the graft
with a grafting twine, tape, or strip, then seal it with grafting wax or
All of the
preceding techniques are used to top work horticultural crops for a
particular purpose. Occasionally, however, grafting is used to repair
injured or diseased plants. Two common techniques available for this
purpose are bridge grafting and inarch grafting.
(Figure 8) is used to "bridge" a diseased or damaged area of a plant,
usually at or near the base of the trunk. Such damage commonly results
from contact with grading or lawn maintenance equipment, or it may be
caused by rodents, cold temperatures, or disease organisms. The bridge
graft provides support as well as a pipeline that allows water and
nutrients to move across the damaged area.
Bridge grafts are
usually done in early spring just before active plant growth begins.
They may be performed any time the bark on the injured plant "slips."
Figure 8. Bridge
Select scions that
are straight and about twice as long as the damaged area to be bridged.
Make a 1 1/2- to 2-inch-long tapered cut on the same plane at each end
of the scion.
Remove any damaged
tissue so the graft is on healthy stems. Cut a flap in the bark on the
rootstock the same width as the scion and below the injury to be
repaired. Gently fold the flap away from the stock, being careful not to
tear the bark flap.
First, insert and
secure the scion below the injury; push the scion under the flap with
the cut portion of the scion against the wood of the injured stem or
trunk. Then go back and insert and secure the scion above the injury
following these same steps. Push the scion firmly into place. Pull the
flap over the scion and tack it into place as described for bark
grafting (Figure 3).
When grafting with
young stems that may waver in the wind, insert the scions so that they
bow outward slightly. Bridge grafts should be spaced about 3 to 4 inches
apart across the damaged area
Secure all graft
areas with warm grafting wax or grafting paint. During and after the
healing period, remove any buds or shoots that develop on the scions.
bridge grafting, is used to bypass or support a damaged or weakened area
of a plant stem (Figure 9). Unlike bridge grafting, the scion can be an
existing shoot, sucker, or water sprout that is already growing below
and extending above the injury. The scion may also be a shoot of the
same species as the injured plant growing on its own root system next to
the main trunk of the damaged tree. With the inarching technique, the
tip of the scion is grafted in above the injury using the same method as
for bark or bridge grafting.
Figure 9. Inarch
scions (most apple tree owners/ orchard growers will usually gladly give
you a bit of scion wood if you ask for it in winter) on to your own
rootstock is a VERY cost effective way of building up a collection of
fruit trees. Rootstocks cost about £2.00 each - and don't forget you can
graft a few different variety scions on to each rootstock!
should also consider is saving the disappearing "heirloom" varieties
from the UK. There are over 1200 native apples for eating, cooking, as
well as for cider making and crab apples for pickling. They have
enchanting names: Acklam Russets, Barnack Beauty, Nutmeg Pippin, Knobby
Russet…and many more. Despite this, most growers concentrate on a few
commercially proven varieties, leaving us with little choice. Worldwide
it's estimated there are 7,500 varieties.
approximately 30 varieties - in TOTAL - between them! The criteria for
variety selection? Uniform size/ shape & colour. Freshness and variety
of flavour is NOT a consideration.
It is estimated
that each fruit is sprayed approximately 18 times with herbicide and
insecticide poisons. They are further sprayed with hormones to aid
storage and induce ripening at a set time (they are harvested before
they are ripe).
Most of them are
flown in from places like South Africa, New Zealand & Australia in the
southern hemisphere, using vast amounts of fuel and causing huge amounts
of pollution. By the time they reach your fruit bowl they already have a
huge carbon footprint.
varieties are disappearing. Others are disappearing the world over. I
challenge you to argue that is sensible or sustainable.
Bring some sanity
back into our lives and grow your own - for yourself, your grandchildren
& great grandchildren - because apple trees can easily produce fruit for
at least three generations. So get grafting!