A Guide to Pruning Fruit Trees
Gardeners expect surprisingly modest yields from their
orchards. I have a friend who always has a superb vegetable
garden, a wonderful Led of roses, and the best strawberry
patch in town. Each tomato is a jewel. Every stalk of corn
produces two large ears, and every flower in his perennial
bed looks as if it is posing for the cover of a garden
magazine. Yet, in spite of his gardening skill, he seems to
be perfectly satisfied to take whatever his fruit trees
hand him.
Often this isn’t very much. He has good fruit when
conditions are perfect, but it’s usually small, misshapen,
poorly colored, and infested with insects. Furthermore, he
typically gets a crop only every other year.
I’m sure that when his trees were young, they were full of
vigor and produced excellent fruit. Young trees almost
always bear large, colorful fruit because they still have
very few limbs, so the fruit gets lots of sunlight.
However, as the trees mature and grow more branches, you
must prune to keep them producing well. Most trees
naturally produce a large crop of fruit every other year,
so if you want your trees to grow an annual crop, you must
give them some special attention. Pruning is a neglected
art, however, and one that novice fruit growers don’t
completely understand.
Pruning fruit trees doesn’t need to be confusing. If you
follow the simple, basic rules, you can leave the
scientific jargon to those who are intrigued by it.
First of all, an orchardist must be aware that his tree
consists of two parts—most fruit trees are grafted.
The roots usually belong to a type of tree that produces
low-quality fruit, whereas the top is a good-bearing
variety that has been transplanted onto the rootstock. The
two have been grafted together because this is the most
efficient way to produce large numbers of quality fruit
trees. Fruit trees grown from seed seldom resemble the
parent tree even slightly, and growing trees from cuttings
or layers is slow and extremely difficult.
Reasons for Pruning
Some gardeners enjoy pruning their fruit trees and
consequently do a good job. However, no one should prune
simply for the fun of it—you should know the reasons
for pruning. All of the following are equally important to
the health and maintenance of your trees:
Prune to get the tree off to a good start.
Although it isn’t easy, you should cut back any bare-rooted
young tree at planting time. When we prune trees for
customers at the nursery, they wince and say that it looks
as if we are slaughtering the poor things, but we assure
them that it is one of the best things you can do to insure
good growth and early crops.
Trees enclosed in a ball of soil or growing in a pot will
not need any cutback. However, bare-rooted trees have
probably been dug recently, and chances are good that some
of the roots have been seriously damaged in the process.
Most mail-order plants are sold bare-rooted, and unless the
directions you receive with the tree indicate that it has
already been done, you should prune both the roots and top
at planting time.
First, cut off any jagged edges on broken roots so they
will heal smoothly. Then cut back the top to make it equal
in size to the root surface. Cut back fruit trees that are
whips—those with no side branches—by at least a
third: If a tree is six feet tall, for example, cut it back
at least two feet, and make the cut on a slant just above a
bud.
If your fruit tree has branches, cut of those that are
weak, dead-looking, broken, or too close to the ground.
Then cut back the top by a third and each strong, healthy
limb by at least a third also. Cut each limb back to an
outside bud so that the next branch will form toward the
outside and the tree will spread outward rather than inward
toward the trunk. (See “Training Young Apple
and Pear Trees.”)
Keep in mind that these directions are only for pruning new
trees. Don’t neglect the other ingredients for proper
planting, like soaking bare-rooted trees for several hours
after arrival, using lots of good soil and water while
planting, and planting to the right depth. Most fruit tree
failures are due to the lack of proper planting as well as
the failure to prune the tree properly at planting time.
Prune lightly to shape the tree during the first
years of its life.
The old saying “as the twig is
bent, so the tree is inclined” is unquestionably true. A
little snipping and pinching here and there while the tree
is young will save you a lot of heavy pruning later on.
If you have trained your tree properly early in its life,
all subsequent pruning will come easier. Whenever you clip
or snip off the buds or tiny twigs, try to keep in mind an
image of the mature tree. Prune in accordance with the
tree’s natural growth habit and for the purpose of’
developing a strong tree with a branch structure sturdy
enough to hold up the crop. Keep the branches sparse enough
to allow the sunshine in to ripen the fruit.
You should prune very little during the tree’s first
years just enough to help shape the tree. Although it’s good
to prune heavily at planting time, this process may cause
it to grow too many branches close to the ground. By
pinching or clipping off all those undesirable new sprouts
during the first years, you will be training the new tree
to grow upright. You’ll also avoid the heavier pruning
which would delay the tree’s first crop.
Some trees need more shaping than others. Many varieties of
apples, such as Wealthy and McIntosh, seem to grow into a
good shape quite naturally. Other varieties, like the
Delicious and Yellow Transparent, tend to grow very
upright, forming lots of tops with bad crotches. If left
uncorrected, these weak crotches and the limbs coming from
them are very likely to break under a heavy load of fruit.
Fruit-loads on plums and cherries are not as heavy as those
on pears and apples. Since they are apt to grow into a
bushy shape no matter what you do, early shaping is
important mainly to keep them from getting too wide or to
prevent the branches from growing too close to the ground.
Some trees grow twiggy naturally, and certain apple
varieties, such as Jonathan, as well as many varieties of
cherries, plums, peaches, and apricots, need additional
thinning of their bearing wood to let in sunshine to ripen
the fruit.
Direct all of your early pruning to guiding the tree into
the desired shape. Fruit trees are usually trained in one
of three forms: central leader, modified leader, or open
center.
Central Leader
Trees that bear heavy crops of
large fruit, including apples and pears, are usually best
pruned to grow with a central leader, or trunk, at least in
their younger days. With only one strong trunk in the
center of the tree, branches come strongly out from it at
fairly wide angles and can safely bear abundant loads of
fruit.
Thin out the branches growing from the central leader as
necessary to allow open space between the limbs. Thin also
the branches that come from these limbs, and so on to the
outermost branches. Sunlight produces colorful, flavorful,
vitamin-enriched fruit. Sunlight and circulating air also
help to prevent scab, mildew, and a host of other diseases
that thrive in shade and high humidity.
Eventually you will have to remove the top of the central
leader because this high-growing leader will gradually sag
under a load of heavy fruit, forming a canopy over part of
the tree that will shut out the light. Cutting back the top
helps prevent a canopy from developing while also keeping
the tree from growing too tall.
Modified Leader
The modified leader method is
initially the same as the central leader method, but
eventually you let the central trunk branch off to form
several tops (see Fig. 3). This training insures that the loads
of fruit at the top of the tree are never as heavy as those
at the bottom, where limbs are larger. Cut back the tops of
larger trees from time to time to shorten the tree or to
let in more light. Although the central leader method is
preferred by most orchardists for growing apples and pears,
the modified leader method is easier to maintain simply
because most fruit trees grow that way naturally.
Open Center
The open center method, also known as
the open top or vase method, is an excellent way to let
more light into the shady interior of a tree (see Fig. 4). Since this method produces a tree with a weaker branch
structure than if it had a strong central leader, the
lightweight fruits are the best subjects: quinces, crab
apples, plums, cherries, peaches, nectarines, and apricots.
Prune so that the limbs forming the vase effect do not all
come out of the main trunk close to each other, or they
will form a cluster of weak crotches. Even with the whole
center of the tree open, you’ll have to thin the branches
and remove the older limbs eventually, just as you would
with a tree pruned in the central leader method.
Prune for good crops of quality fruit.
Good fruit needs plenty of sunshine, and a fruit tree
fortunately has a potentially large area to produce fruit:
a full-size, standard tree can be well over 30 feet wide
and 20 feet high. However, only 30% of an unpruned tree,
because of its tight branch structure, gets enough light,
while another 40% gets only a fair amount of light. As
these percentages indicate, when only the top exterior of
the tree produces good fruit, you are getting the use of
but a third of your tree, and all that fruit is grown where
it is most difficult to pick. Even the most careful pruning
won’t bring the light efficiency to a full 100%, but you
can greatly increase it.
The drawings in Figs. 5 and 6 illustrate the theory of
pruning to let the light in. Since a fruit tree is
three-dimensional, your tree won’t look just like the
drawings. They are exaggerated to show why pruning should
be done and how it lets more light into the tree.
Another way to improve the quality of your fruit is to
remove the surplus fruit whenever your tree sets too many
(see Fig. 7). Although regular pruning will cut down the number
of fruits produced, a tree may still bear a greater number
than it can develop to a large size. The production of too
many seeds seems to tax a tree’s strength, and certain
varieties of fruits seem bent on bearing themselves to
death, unless you give them a helping hand. When a tree
bears too many fruits in any one year, it usually bears
few, if any, fruits the following year. Thin out extras
when they are small. Most trees, as well as their fruits,
benefit if you leave only one fruit remaining in each
cluster. Make sure that each fruit is at least six inches
from its neighbor on either side.
Prune to keep your trees from getting too large. Since standard-size fruit trees can grow to 25 feet or
more, they are often pruned to keep them at a more
manageable height. A tall tree is difficult and dangerous
to work in. And, because so much of the tree is shaded, it
often produces poor fruit.
Of course it’s best to prune regularly so that your tree
won’t get too tall in the first place, but if this advice
comes too late, consider shortening it. The tree should be
healthy enough to stand major surgery. Make sure that there
will be enough lower branches left on the tree to sustain
it after its upper level has been removed: The leaf surface
remaining must be adequate to supply nutrients to the tree.
If these conditions can be met, begin to prune back the top
in late summer or early fall. Make the cuts in small
stages, cutting off only small pieces of limbs at one time,
so that the limb weight will be lessened before you begin
the heavy cutting. These small cuts lessen the danger of
splitting limbs, and also help insure that you won’t drop
heavy pieces of wood onto the lower branches. If possible,
have a helper handy to catch the limbs as they fall or to
guide them away from the tree (see Fig. 8).
Don’t cut off more than one large limb in any one year.
Make sure that some regrowth has started on the lower
branches before you make any further cuts. Like an obese
person, the tree got into its overgrown condition over a
period of many years, so don’t try to correct all its
problems at once.
Prune to keep your tree healthy.
Even
young fruit trees occasionally need to be pruned because of
some mishap: Limbs get broken, tent caterpillars build
nests, and as the tree gets older, rot and winter injury
often take their toll on the branches.
As soon as you notice any damage, clip or saw off the
injured part back to a live limb or to the trunk. Even one
deteriorating limb is not good for the tree’s health, and
the accumulation of several sick limbs will speed up the
decline of the tree.
Rejuvenation is vital to a tree’s health, especially when
your goal is to produce good crops of high-quality fruit
over a number of years. Many trees that produce handsome
specimens while they are young or middle-aged often bear
only small, poor fruit as they grow older. By replacing and
renewing the old bearing wood, you encourage the tree to
continue bringing forth large red apples or big crops of
juicy plums or peaches.
As with every other kind of pruning, you’ll get the best
results from rejuvenation pruning when you do it on an
annual basis rather than as an occasional event. If you
remove a few of the older limbs each year to open up the
tree to sunlight and air, the whole bearing surface can be
renewed every six or eight years, which is like getting a
whole new tree. In addition, because you will seldom need
to do any drastic pruning of large, heavy limbs, the tree
will suffer less.
Large limbs should grow only as an extension of the tree
trunk itself, and as a unit from which the small limbs
grow. These overlarge limbs are a tremendous strain on the
tree, so the fewer, the better. Because fruit trees are
pruned more heavily than most other plant life, heavy limb
growth is much more likely to result than when a tree is
left unpruned or lightly pruned. Cut off crossed branches
or branches that might rub to cause wounds in the bark
(see Fig. 9).
Water sprouts are those upright branches that grow in
clumps, often from a large pruning wound (see Fig. 10). They
are usually unproductive, and they can weaken the tree by
causing additional, unwanted shade. You should remove water
sprouts promptly.
Suckers are the branches that grow on the lower part of the
tree trunk or from the roots of the tree (see Fig. 10). Usually
they grow from below the graft, so if you don’t remove
them, they’ll grow into a wild tree or bush that will crowd
out the good part of the tree within a few years. A lot of
sucker growth results on fruit trees when a slower-growing
variety is grafted onto a vigorous-growing rootstock.
Usually the suckers appear as a cluster of branches close
to the base of the tree trunk, but sometimes (especially on
plum trees) they may pop up out of the roots anywhere under
the tree, even a distance away from the trunk. Mow or clip
them off at ground level as soon as they appear.
When to Prune Fruit Trees
There is an ever-continuing argument among pomologists
about the best time to prune fruit trees. Magazines often
run articles supporting one time of year or another, and
each professional orchardist and experienced home grower
has a favorite time. Meanwhile, beginners can get
completely confused listening to the controversy.
Perhaps the best way to help answer the question is to
describe what happens when you prune at different seasons.
Seasonal conditions vary greatly throughout the country, so
your location is an important factor in determining when
you should prune.
Spring. Most people agree that pruning a
fruit tree when it is just beginning to make its most
active growth is one of the worst times. The tree will
probably bleed heavily, and it may have trouble recovering
from the loss of so much sap. Also, infections such as fire
blight are most active and easily spread around in the
spring. If a book suggests pruning in the early spring, the
author often means late winter-before any growth begins.
The only pruning you should do in the spring is to remove
any branches that have been broken by winter storms or
injured by the cold. Immediately tack bark that has split
from the trunk back onto the wood, and seal the wound with
tree dressing to prevent air from drying the bare wood.
Early summer. Although I don’t recommend
major pruning in early summer, this is a good time to pinch
off buds and snip off small branches that are growing in
the wrong direction or in the wrong place. Remove suckers,
water sprouts, and branches that have formed too low on the
stem as soon as you notice them.
Late summer. Late summer is a favorite
time for many people to prune their fruit trees. By pruning
after the tree has completed its yearly growth and hardened
its wood and before it has lost its leaves, you stimulate
less regrowth. You still have to take care of any frost
injury in late winter, but this late summer-early fall
pruning works well if extensive winter damage is not
likely.
Wherever growing seasons are short and the extreme cold or
heavy snow and ice loads may cause injury to the trees,
late-winter pruning is best. Don’t cut back the tree in
late summer if there’s a good chance that the remaining
branches will be winter-killed. You’ll have to prune away
too much of the tree.
Late fall and winter. Late fall or winter
is a favorite time to prune in the warmer parts of the
country. Orchardists have more spare time then, and the
trees are bare, so it is easier to see what needs to be
done. You should choose days when the temperature is above
freezing, however, to avoid injury to the wood. Because
frozen wood is very brittle, it breaks easily when hit.
However, if you live in a cold part of the country, or if
you are growing tree varieties that are inclined to have
winter injury, wait until the coldest weather is over
before pruning.
Late winter. This season is probably the
most popular time for northern gardeners to prune. As in
late fall and winter, the tree is completely dormant, and
since the leaves are off, it is easy to see where to make
the cuts. You can repair any winter injury, the weather is
usually warm enough during the day, and most orchardists
are not too busy during this season.
If you prune your trees regularly each year, late winter is
a satisfactory time to prune because you don’t have to
remove large amounts of wood. However, if the trees have
been neglected for a few years and are badly in need of a
cutback, late winter is not the best time to prune.
Excessive pruning in late winter usually stimulates a great
deal of growth the following spring and summer, because the
tree tries to replace its lost wood. Branches, suckers, and
water sprouts are likely to grow in great abundance. If a
major pruning job is necessary, do all or at least a large
part of it in late summer or early fall so that you won’t
cause a great amount of regrowth.
MOTHER’S HANDBOOK: This excerpt from Lewis Hill’s Pruning Simplified shows how to improve tree health by pruning fruit trees.
Pruning Sanitation of Fruit Trees
Some of the most serious diseases are carried by pruning
tools. Fire blight, for example, a bacteria-caused disease
that is lethal to fruit trees, has spread around many
orchards this way. (See pruning sanitation diagrams).
Training Young apple and pear
trees
If you suspect disease, think of yourself as a tree doctor
as you prune. You wouldn’t expect a surgeon to take out
your gallbladder with the same dirty instruments he had
used to remove his last patient’s appendix. Your prized
Bartlett pear deserves careful treatment, with tools that
have been disinfected.
If you feel that there might be disease in your orchard,
disinfect your gloves and tools after pruning each tree.
Professional orchardists often use a mixture of bichloride
of mercury and cyanide of mercury for this purpose, but
both of these chemicals are very poisonous and are not
recommended for home use. For the home orchardist, it is
safer and quite effective to soak the tools in a pail
containing full-strength Clorox or similar home bleach as
you go between branches or trees. With these germ-free
tools, you can approach your patients with a clear
conscience and not feel they are drawing their limbs about
them in fear and trembling.
Disease also spreads around the orchard via the wind and
insects. A good way to keep fungus, germs, and insects out
of a tree is to seal up all cuts and open wounds with an
antiseptic paint. Most tree infections are especially
active in the spring, so do your painting and sealing early
in the season before they get started. Remove all of the
pruning debris from the area, and either burn it or take it
to a dump or landfill.
