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Vine Pruning In California








The systems of pruning in use in California may be divided into two
classes according to the arrangement of the arms on the trunk of the
vine. In the commonest systems, there is a definite head to the trunk,
from which all the arms arise symmetrically at nearly the same level.
The vines of these systems may be called "headed vines." In the other
systems, the trunk is elongated four to eight feet and the arms are
distributed regularly along the whole or the greater portion of its
length. The vines of these systems, owing to the rope-like form of the
trunks, are called "cordons."

The headed vines are divided according to the length of the vertical
trunk into high, 2-3 feet, medium, 1-1-1/2 feet, and low, 0-6 inches.
The cordons may be vertical or horizontal, according to the direction
of the trunk, which is from four to eight feet long. The horizontal
cordons may be single (unilateral) or composed of two branches
extending in opposite directions (bilateral). Double and even multiple
vertical cordons occur, but they are very inadvisable and have no
advantages.

The arrangement of the arms of a headed vine may be symmetrical in all
directions at an angle of about 45 degrees. Such a vine is said to be
"vase-formed," though the hollow center which this term implies is not
essential. This is the form used in the great majority of our
vineyards whether of wine, raisin, or shipping grapes. It is suitable
for the "square" system of planting and cross cultivation. Where vines
are planted in the avenue system, particularly when trellised and
where cross cultivation is impossible, the arms are given a
"fan-shaped" arrangement in a vertical plane. This arrangement is
considered to be essential for the economical and easy working of
trellised vines.

On the vertical or upright cordon, the arms are arranged at as regular
intervals as possible on all sides of the trunk from the top to within
twelve or fifteen inches of the bottom. On the horizontal cordon the
arms are arranged similarly, but as nearly as possible on the upper
side of the trunk only.

Each of these systems may again be divided into two subsystems,
according to the management of the annual growth or canes. In one,
spurs of one, two, or three eyes are left for fruit production. This
system is called short or spur pruning. In the other, long canes are
left for fruit production. This is called long or cane pruning. In
rare cases an intermediate form is adopted in which long spurs or
short canes of five or six eyes are left. In cane pruning, each fruit
cane is accompanied by one or two short renewal spurs. These must also
accompany half-long pruning. Systems of pruning, when only long canes
are left without renewal-spurs, are not in use in California. In all
systems, replacing-spurs are left wherever and whenever needed.

Other modifications are introduced by the manner of disposal of the
fruit canes. These may be tied up vertically to a stake driven at the
foot of each vine or bowed in a circle and tied to this same stake, or
they may be tied laterally to wires stretching along the rows in a
horizontal, ascending or descending direction.

The different systems differ therefore in: (1) the shape, length, and
direction of the trunk; (2) the arrangement of the arms; (3) the use
of fruit spurs or fruit canes with renewal spurs; (4) the disposal of
the fruit canes.

The principal possibilities of the pruning are shown in the following
table:


A. HEAD PRUNING: VASE-FORM

} { (a) Fruit spurs or
} {
1. High trunk: } { (b) Half-long canes and renewal
} { spurs or
2. Medium trunk: } with {
} { (c) Fruit canes and renewal
3. Low trunk: } { spurs; canes vertical
} { or bowed.


B. HEAD PRUNING: FAN-SHAPED; TRELLISED

1. High trunk: Fruit canes and renewal spurs; canes descending.

2. Medium trunk: Fruit canes and renewal spurs; canes horizontal or
ascending.


C. CORDON PRUNING

1. Vertical: Spur; half-long; cane.

2. Horizontal-unilateral: Spur; half-long; cane.

3. Horizontal-bilateral: Spur; half-long; cane.

All possible combinations indicated by this table represent 24
variations. Some of these combinations, however, are not used and some
are rare. The most common are shown in Figs. 23, 24, 25, 26 and 27.

Figure 23 B represents a headed, vase-formed vine, with a medium trunk
and short fruit spurs. This is the most common system used in all
parts of California and is suited for all small growing vines which
bear on the lower buds, for most wine grapes and for Muscats. The unit
of pruning in this case is a fruit spur of 1, 2, or 3 internodes,
according to the vigor of the variety and of the individual cane.

Figure 23 A differs from 23 B only in the higher trunk and longer
arms. It is commonly used for Tokay and other large growing
varieties, especially when growing in rich soil and when planted far
apart.


high trunk; B, spur pruning with medium trunk; C, half-long with
medium trunk.]

Figure 23 C has the same form of body as A and B, except that the arms
are somewhat less numerous. The unit of pruning is a short fruit cane
of four to five internodes, accompanied by a renewal spur of one
internode. It is suited for vigorous table grapes, which do not bear
well on short spurs. It is used especially for the Cornichon and
Malaga in rich soil. This is a difficult system to keep in good shape
owing to the tendency for all the vigor to go to the growth on the
ends of the fruit canes. It is difficult to obtain vigorous canes on
the renewal spurs. Occasional short pruning is usually necessary to
keep the vines in proper shape.

Figure 24 A is similar to 23 C in form, but the number of arms is
still further reduced to 2, 3, or at most 4. The unit of pruning is a
fruit cane of 2-1/2 to 3-1/2 feet with its renewal spur. Owing to the
length of the fruit canes they require support and are tied to a high
stake.

This method is used in a large number of vineyards with Sultanina,
Sultana and certain wine grapes, especially Semillon and Cabernet. It
is not to be recommended in any case, as it has several very serious
defects.

The difficulty of obtaining new wood from the renewal spurs is even
greater than in the system shown in Fig. 23 C. The length and vertical
position of the fruit canes cause the main growth and vigor of the
vine to be expended on the highest shoots. The renewal spurs are thus
so shaded that, even though their buds start, the shoots make but a
weak growth. The result is that at the following pruning all the good
new wood is at the top of the fruit canes of the previous year, where
it cannot be utilized. The pruner has to choose then between reverting
to spur pruning and getting no crop or using the weak growth from the
renewal spurs for fruit canes, in which case he may get blossoms but
little or no fruit of any value.


canes and renewal spurs; B, bowed fruit canes and renewal spurs.]

Other defects of this method are that the fruiting shoots are
excessively vigorous and therefore often tend to drop their blossoms
without setting and the fruit when produced is massed together so that
it ripens unevenly and is difficult to gather. It also requires a tall
and expensive stake.

Figure 24 B represents an improvement on the last system. It differs
only in the method of treating the fruit canes. These are bent over
in the form of a circle and tied by their middle part to a stake which
may be smaller and lower than that needed for the vertical canes.

This bowing of the canes has several useful effects. The change of
direction moderates the tendency of the vigor of the vine to expend
itself only on the terminal shoots. More shoots therefore are formed
on the fruit canes and as their vigor is somewhat decreased they tend
to be more fruitful. The slight mechanical injury caused by the
bending operates in the same direction.


tied to horizontal trellis.]

The excess of vigor thus being diverted from the fruit canes causes
the renewal spurs to form vigorous shoots, which soon grow above the
fruit shoots and obtain the light and air they need for their proper
development. This method is used successfully for certain wine grapes
such as Riesling, Cabernet, and Semillon. It is unsuited to large
vigorous varieties or for vines on rich soil planted wide apart. In
these cases two fruit canes are usually insufficient and, if more are
used, the grapes and leaves are so massed together that they are
subject to mildew and do not ripen evenly or well. The bowing and
tying of the canes requires considerable skill and care on the part of
the workmen.

The body, arms, and annual pruning of the system shown in Fig. 25 are
similar to those of Fig. 24, with the exception that the arms are
given a fan-shaped arrangement in one plane. It differs in the
disposal of the fruit canes, which are supported by a trellis
stretching along the row from vine to vine.

This method is largely used for the Sultanina (Thompson's Seedless),
and is the best system for vigorous vines which require long pruning,
wherever it is possible to dispense with cross cultivation. It is also
suitable for any long-pruned varieties when growing in very fertile
soil.

Figure 26 is a photograph of a four-year-old Emperor vine,
illustrating the vertical cordon system. It consists of an upright
trunk 4-1/2 feet high with short arms and fruit spurs scattered evenly
and symmetrically from the top to within fifteen inches of the bottom.
This system is used in many Emperor vineyards in the San Joaquin
Valley.



Its advantages are that it allows the large development of the vine
and the large number of spurs which the vigor of the Emperor demands,
without, on the one hand, crowding the fruit by the proximity of the
spurs or, on the other hand, spreading the vine so much that
cultivation is interfered with. It also permits cross cultivation.


One of its defects is that the fruit is subjected to various degrees
of temperature and shading in different parts of the vine and the
ripening and coloring are often uneven. A more vital defect is that it
cannot be maintained permanently. The arms and spurs at the top of
the trunk tend to absorb the energies of the vine and the lower arms
and spurs become weaker each year until finally no growth at all is
obtained below. After several years, most of the vines therefore lose
their character of cordons and become simply headed-vines with
abnormally long trunks.

The cordon can be reestablished in this case by allowing a vigorous
sucker to develop one year from which to form a new trunk the next.
The following year the old trunk is removed entirely. An objection to
this method is that it makes very large wounds in the most vital part
of the vine--the base of the trunk.

Figure 27 is a photograph of a four-year-old Colombar vine,
illustrating the unilateral, horizontal cordon system. It consists of
a trunk about seven feet long, supported horizontally by a wire two
feet from the ground. Arms and spurs are arranged along the whole
horizontal part of the trunk.


spurs.]

This system accomplishes the same objects as the vertical cordon. It
allows a large development of the vine and numerous fruit spurs
without crowding. It is superior to the vertical cordon in the
distribution of the fruit, which is all exposed to approximately the
same conditions owing to the uniform distance from the ground of the
fruit spurs. All parts of the trunk producing an annual growth of wood
and fruit are equally exposed to light and the tendency of the growth
to occur principally at the part of the trunk farthest removed from
the root is counteracted by the horizontal position. There is not the
same difficulty therefore in maintaining this form of vine permanently
that there is with the vertical cordon.

This system should not be used for small weak vines, whether the
weakness is a characteristic of the variety or due to the nature of
the soil. It is suited only to very vigorous varieties such as
Emperor, Almeria, and the Persian grapes when growing far apart in
rich, moist soil.

Periods of development.

The first year in the life of a vine is devoted to developing a
vigorous root system; the next two or three years to building up a
shapely trunk and head, and a like period to forming the full
complement of arms. At the end of from five to nine years the
framework of the vine is complete and should undergo no particular
change of shape except a gradual thickening of trunk and arms.

There are, therefore, several periods in the life of the vine with
varying objects, and the methods of pruning must vary accordingly.
These periods do not correspond exactly to periods of time, so it may
be misleading to speak of pruning a two-year-old or a three-year-old
vine. One vine under certain conditions will reach the same stage of
development in two years that another will reach only in three or four
years under other conditions. The range of time of these periods is
about as follows:

First period--Formation of a strong root system 1 to 2 years
Second period--Formation of stem or trunk 1 year
Third period--Formation of head 2 to 3 years
Fourth period--Complete development of the arms 2 to 3 years
Total time of formation of framework 6 to 9 years

Under exceptionally favorable conditions the first and second periods
may be included in the first year and a completely formed vine may be
obtained in five years.

Before planting.

For planting, cuttings, one-year-old rooted vines, or bench grafts are
used. In all cases, they need some attention from the pruner.

The usual way to prune a good rooted vine of average size having a
single cane at the top and several good roots at the bottom is to
shorten the cane to one or two buds and the roots to two or four
inches, according to their size. Shortening the cane makes the vine
less liable to dry out before rooting and forces the growth from the
lower buds which produce more vigorous shoots. The roots are shortened
so that there will be no danger of the ends being turned upwards when
planted. If they are to be planted in a large hole, they may be left
as long as five or six inches; if to be planted with a crowbar or
dibble, they must be cut back to half an inch.

If the rooted vine has several canes, all but one should be removed
entirely, and this one shortened to one or two eyes. The one left
should be that which is strongest, has the best buds, and is the best
placed. Where a horizontal cane is left, it should be cut back to the
base bud. Otherwise the main growth may occur at a higher bud and the
vine will have a crook which will result in a badly formed trunk.

If canes are growing from different joints, it is usually best to
leave the lower cane if they are equally vigorous. This brings the
buds from which growth will come nearer to the roots, and leaves less
of the original cutting, which are advantages. The upper joint between
the canes is, moreover, often more or less decayed or imperfect.

First growing season.

The treatment during the first spring and summer will depend on what
growth the vines are expected to make and on whether the vines are
staked the first year.

With cuttings and with both rooted vines and grafts where the growth
will be moderate, staking the first year is unnecessary, though it has
some slight advantages. In these cases, no pruning of any kind is
necessary until the winter following the planting, except in the case
of bench grafts. The pruning in the last case is confined to the
removal of the suckers from the stock and roots from the cion. If the
stocks have been well disbudded by the nurseryman, few suckers will
develop. In moist soil, the cion roots may develop vigorously and must
be removed before they grow too large, or they may prevent the proper
development of the resistant roots.

The removal of roots should usually be done some time in July. For
this purpose the hill of soil is scraped away from the union and after
the cion roots and suckers are removed it is replaced. In this second
hilling up, the union should be just barely covered so that the soil
round the union will be dry and unfavorable to a second growth of
roots. Later in the season, about September, the soil should be
removed entirely from around the union and any new roots that may have
formed removed. The union is then left exposed to harden and mature,
so that it will pass the winter without injury.

First winter pruning.

At the end of the first growing season, an average good vine will have
produced from three to five canes, the longest of which will be from
two to three feet long.

Soon after the leaves have fallen in December or early in January the
vines should be pruned. The method is precisely similar to that used
for rooted vines before planting except that the main roots are not
touched. All the canes are removed entirely except one. This one
should be well matured, at least at the base, and should have
well-formed eyes. It is shortened to two eyes. It is well also to cut
off all shallow roots within three or four inches of the surface. This
is necessary in the case of grafted vines if any have escaped the
summer root-cutting.

Some of the vines may have made an exceptionally large growth. Such
vines may sometimes possess a cane large enough from which to start
the trunk in the way described later for the second winter pruning.

Staking.

If the vines have not been staked before, the stakes should be driven
soon after pruning and before the starting of the buds.

In order to preserve the alignment of the vineyard, the stakes should
be driven on the same side of every vine at a uniform distance. The
best distance is about two inches. If driven closer they may injure
large roots or even the main underground stem if the vines have not
been carefully planted vertically or slanting towards the side on
which the stake is to be placed.

The side on which the stake should be placed depends on the direction
of the prevailing winds during the growing season. This side is the
leeward. That is, the stake should be so placed that the wind will
press the vine towards the stake instead of away from it. This will
much facilitate the work of keeping the vine upright and attached to
the stake. If the vine is on the other side the pressure of the wind
will stretch the string tight and the swaying of the vine will
gradually wear the string until it breaks, necessitating retying. By
carefully observing this rule, very few vines will require retying
even if weak material like binding twine is used.

Second summer pruning.

Before the starting of the buds, in the spring following the planting,
most of the vines appear about the same as when they were planted.
There is, however, a very notable difference, in that they have
well-developed root systems in the soil where they were formed. The
result is that they make a much more prompt and early start and will
produce a much larger growth than they did the first season. For this
reason they require very careful attention from the pruner during the
spring and summer of the second season. Vines neglected at this time,
in this respect, may make as large a growth, but a large part of it
will be wasted, the vines will be misformed and it will require from
one to two years longer to develop a suitable framework and to bring
them into bearing, even though they are properly handled during
subsequent years. The more vigorous the vines, the more necessary it
is to handle them properly during this period.

The main object during this second growing season is to develop a
single, strong, vigorous and well-ripened cane from which to form the
permanent trunk of the vine.

This is done by concentrating all the energies of the vine into the
growth of a single shoot. As soon as the buds start, or when the most
precocious has developed a shoot of a few inches in length, the vines
should be disbudded. This consists in rubbing off with the hand all
buds and shoots except the two largest and best placed. The lowest,
upright shoots are usually the best. Leave only those which will make
a straight vine. It is better to leave less developed buds than a
shoot which, when it grows, will make an awkward crook with the
underground stem.

After this disbudding, the two shoots left will grow rapidly, as they
receive all the energies of the root system. When the longest have
grown from ten to fifteen inches, they should be tied to the stake.
Unless this is done, they are liable to be broken off by any heavy
wind, owing to their soft, succulent texture. Only the best placed and
most vigorous of the two shoots should be tied up. If this shoot is
growing upright and near the stake, this can be done without any
danger of injuring it. In this case the second shoot should be
removed. If the shoot has to be bent over in tying it to the stake it
may be injured. In such a case the second shoot should be allowed to
grow until it is known whether the first has been injured. In case of
injury the second shoot can be tied up the next time the vines are
visited and the injured shoot removed.

At the tying up of the reserved shoots, all new shoots which have
developed since the first disbudding should be removed. The shoots
should be tied up loosely, as they are soft and easily injured, and
they should be brought around carefully to the windward side of the
stake.

The shoots will require tying once more when they have grown another
foot or eighteen inches. There will then be two ties, one at two or
three inches from the top of the stake and the other at about the
middle. If the vines have a tall stake and are to be headed very high,
another tying higher up may be needed later.

With vines making only a moderate growth, no other pruning will be
needed until the winter. Exceptionally vigorous vines, however, may
make a cane eight, ten or more feet long. Such a cane is heavy and is
very likely to break the ropes by which it is attached to the stake.
In this case it may break off at the bottom, or at least will form an
awkward crook near the ground when it matures. In either case it is
difficult to form a good trunk the following year. Even when the ties
do not break, the cane will not be well suited for the commencement of
a trunk, as the joints will be so long that it will be impossible to
leave enough well-placed buds at the winter pruning.

Both these difficulties are avoided by timely topping. When such
vigorously growing canes have grown twelve or eighteen inches above
the top of the stake they are cut back about level with the stake.
This is most conveniently done with a long-bladed knife or piece of
split bamboo. After topping, the cane ceases to grow in length and
laterals start at most of the joints. It is less exposed to the
action of the wind, and the laterals supply the buds needed for
forming the vine at the winter pruning.



The result of the second season's growth, then, has been to produce a
single vigorous cane with or without laterals. This is the cane which
is to develop into the final and permanent trunk of the vine. It must
not only be large and vigorous, but must be properly matured. If the
vine is allowed to grow too late in the season, an early frost may
destroy the unmatured cane, and much of the results of the year's
growth will be wasted. Such a frost may indeed kill the entire vine.
Grafted vines are particularly liable to injury from this cause, as if
they are killed down to the union they are completely ruined.
Ungrafted vines when killed to the ground may be renewed from a sucker
next year. This sucker, however, is likely to grow with such vigor
that it is even more liable to injury from an autumn frost than the
original shoot.

This late growth is much more likely to occur with young vines than
with old. The old vines stop growing earlier because their energies
are directed into the crop, and as they produce a larger amount of
foliage they draw more upon the moisture of the soil, which therefore
dries out earlier.

Late growth of the young vines must be prevented and the wood matured
before frost if possible. This is accomplished by means which promote
the drying of the soil in autumn. Late irrigations should be avoided.
Cultivation should usually stop by midsummer. In very moist, rich
soils, it is often an advantage to grow corn, sunflowers or similar
crops between the rows of vines to take off the surplus moisture. In
some cases it is good practice to let the summer weeds grow for the
same purpose.

Second winter pruning.

With vines which have been treated as described and to which no
accident has happened, the second winter pruning is very simple. It
consists simply in cutting back the single cane which has been allowed
to grow to the height at which it is desired to head the vine.

The vine so pruned consists of a single cane which with the older wood
at the base reaches nearly to the top of the stake, or fifteen inches.
This if properly treated will develop into a vine with a trunk of
about twelve inches, though this length can be modified slightly, as
will be explained later.

This cane consists of about seven or eight joints or internodes, with
an equal number of well-formed eyes and an indefinite number of
dormant buds, principally near the base of the cane or junction of the
one- and two-year-old wood. Only the buds on the upper half of this
cane will be allowed to grow. These buds--about four--should give six
to eight bunches of grapes and four, six, or eight shoots from which
to form the spurs at the following winter pruning.

With a vine which has been cut back to form a high head, the cane is
about twenty-four inches long and can be used to form a trunk eighteen
inches high, though this height can be modified as in the last case.
As with the shorter cane, only the buds on the upper half will be
allowed to produce shoots. These--about six--should give ten to twelve
bunches and the shoots necessary for the formation of spurs.

In all cases a full internode has been left above the top bud. This is
done by cutting through the first bud above the highest which it is
desired to have grow. This cut is made in such a way as to destroy the
bud but to leave the diaphragm intact and part of the swelling of the
node. This upper internode is left partly to protect the upper bud,
but principally to facilitate tying. By making a half-hitch around
this internode, the vine is held very firmly. If the swelling at the
node of the destroyed bud is not left, many vines will be pulled out
of the hitch when they become heavy with leaves and supple with the
flow of sap in the spring.

In tying the vines, no turns or hitches must be made around any part
except this upper internode. A hitch below the top bud will result in
a crook-necked vine, as the top will bend over in the summer under the
weight of the foliage. A hitch lower down is even more harmful, as it
will girdle and strangle the vine.

A second tie about half way from the upper to the ground is always
necessary to straighten the cane. Even if the cane is straight when
pruned, a second tie is needed to keep it from curving under the
pressure of leaves and wind in the spring. For high-headed vines three
ties are usually necessary.

For the top tie, wire is particularly suitable. It holds better than
twine and does not wear. Even though it is not removed, it does no
harm, as the part around which it is wound does not grow. The lower
ties should be of softer material, as wire has a tendency to cut into
the wood. They should be placed so that the cane is able to expand as
it grows. With thin and especially with round stakes this means that
the tie must be loose. With large, square stakes there is usually
sufficient room for expansion, even when the twine is tied tight.

Third summer pruning.

During the third season, average well-grown vines will produce their
first considerable crop and develop the canes from which will be
formed the first arms.

Such a vine, soon after the starting of the buds in spring, will have
one vigorous shoot about three inches long grown from the old wood and
five fruit buds started above on the cane. All the buds and shoots
below the middle of the cane should be removed.

This will leave the four or five fruit buds and will give the vine the
opportunity to produce eight or ten bunches of grapes. These buds will
produce also at least four or five shoots. If the vine is very
vigorous and the season favorable, they may produce eight, ten or
more.

When the five shoots grow, the height of the head will be determined
at the next winter pruning by which of the corresponding canes are
left as spurs. If the highest two canes are cut back to spurs and all
others removed, the vine will be headed as high as possible, as these
two spurs form the two first arms which determine the length of the
trunk. If the lowest two canes are chosen and all of the vine above
them removed, the trunk will be made as low as possible. Intermediate
heights can be obtained by using some other two adjacent canes and
removing the rest. It is often advisable to leave some extra spurs
lower than it is desired to head the vine and to remove these lower
spurs the following winter after they have borne a crop. For example,
the three or four upper canes might be left, if the vine is vigorous
enough, and the lowest one or two of these removed at the next
pruning. This, however, is not often necessary with properly handled
vines and is objectionable because it makes large wounds in the trunk.

Third winter pruning.

At the end of the third season's growth the vine should have a
straight, well-developed trunk with a number of vigorous canes near
the top from which to form the arms.

Figure 28 represents a well-grown vine at this period. No shoots have
been allowed to grow on the lower part of the trunk and the five buds
allowed to grow above have produced nine vigorous canes. The pruner
should leave enough spurs to supply all the fruit buds that the vine
can utilize. The number, size and thickness of the canes show that the
vine is very vigorous and can support a large crop. It will depend
somewhat on the variety how many buds should be left. For a variety
whose bunches average one pound, and which produces two bunches to the
shoot, twelve fruit buds should give about twenty-four pounds, or
about seven tons per acre, if the vines are planted 12 by 6 feet, as
these were. The number of spurs will depend on their length. Six spurs
of two buds each will give the required number, but as some of these
canes are exceptionally vigorous they should be left a little longer,
in which case a smaller number of spurs will suffice.



When the number and length of the spurs are decided on, the canes
should be chosen which will leave these spurs in the most suitable
position for forming arms. This position will depend on whether we
want a vase-form or fan-shaped vine. In the first case, we choose
those which will distribute the spurs most evenly and symmetrically on
all sides, avoiding any which cross or point downwards.

In the second case, we choose only those canes which run in the
direction of the trellis, avoiding canes which stick out between the
rows. Downward pointing canes may be used in this case.


head.]

Figure 29 shows the vine after pruning for a vase-formed head. The
pruner has used two of the strongest canes to form two three-bud
spurs and three of medium vigor to form three two-bud spurs. The head
is of good shape, though some of the spurs are a little too low. One,
two, or three of these can be removed at the following winter pruning,
and the permanent arms and head of the vine formed from canes which
develop on the two highest spurs. If the vine were too high, the head
could be developed the next year from the three lowest spurs and the
upper part removed.


vase-formed, and B, for a fan-shaped head.]

Figure 30 shows vines of the same age of practically perfect shape.
Less spurs have been left because the vines were less vigorous. It is
easier to properly shape vines which make only a moderate growth
during the first three seasons. On the other hand, very vigorous vines
can finally be brought into practically perfect shape and the somewhat
larger and more numerous wounds necessary are more easily healed by a
vigorous vine.

Pruning after the third winter.

For the pruner who understands the pruning of young vines and has
brought them to approximately the form represented in Figs. 29 and 30,
the subsequent winter pruning is very simple. It involves, however,
one new idea--the distinction between fruit and sterile wood.

Up to the third winter pruning, this distinction is not necessary;
first, because practically all the wood is fruit wood, and second,
because the necessity of forming the vine controls the choice of wood.
From this time on, however, this distinction must be carefully made.
At each winter pruning a number of spurs of fruit wood must be left to
produce the crop to be expected from the size and vigor of the vine.
Besides these fruit spurs, it may be necessary to leave spurs of
sterile wood to permit of increasing the number of fruit spurs the
following year.

This will be made clear by comparing Figs. 30 A and 31. Figure 30 A
shows a vine at the third winter pruning with two fruit spurs of two
buds each and one fruit spur of one bud--five fruit buds in all.

If these five fruit buds all produce vigorous shoots during the
following summer, they will supply five canes of fruit wood which can
be used to form five fruit spurs at the following winter pruning,
which will be about the normal increase necessary. Some of these fruit
buds, however, may produce weak shoots or shoots so badly placed that
they would spoil the shape of the head if used for spurs. Other
shoots, however, will be produced from base, secondary and
adventitious buds which, while less fruitful, can be used to form
spurs for the starting of new arms.


head.]

Figure 31 shows a vine after the fourth winter pruning which had
developed from a vine similar to that shown in Fig. 30 A. From the
three fruit spurs left the previous year four canes have been chosen
for the fruit spurs of this year. The old spur on the left has
furnished two new spurs and the two old spurs at the right each one
new spur. The pruner, judging that the vine is sufficiently vigorous
to stand more wood, has formed two spurs from water sprouts which,
while not likely to produce much fruit the first season, will supply
fruit wood for the following year. The result is a very well-shaped
vine with six almost perfectly balanced spurs. These spurs will
develop into permanent arms, some of them furnishing finally two or
three.

Figure 32 shows a high-headed vine of the same age. It has five spurs,
of which four are fruit spurs and one a spur of sterile wood left to
shape the vine. The two more or less horizontal spurs on the right
will bear fruit the following autumn and will be removed entirely at
the following winter pruning, as they are badly placed. The arms of
the vine will then be developed from the three upright spurs, which
are excellently placed.


head.]

Each year thereafter the same process must be followed. First, enough
fruit spurs, as well placed as possible, must be left to produce the
crop. Second, on most vines supplementary spurs of sterile wood must
be left to supply more arms where they are needed, and finally, when
the full complement of arms has developed, to supply new arms to
replace those which have become too long or are otherwise defective.

Fan-shaped vines.

With headed vines, the treatment up to the third winter is the same
except for the variations in the height of the head. At the third
winter pruning, however, the formation of the head commences, and the
pruner determines whether it shall be vase-formed or fan-shaped. The
production of a vase-formed head has already been described.

At the third winter pruning, the vine should be pruned to two spurs,
as shown in Fig. 30 B. More vigorous vines should not be given more
spurs, as in Figs. 29 and 30 A, but the spurs should be made longer,
with four, five, or even six eyes in some cases. This is in order to
obtain some fruit, which might not be obtained from long pruning
varieties by leaving many spurs. With extremely vigorous vines one
fruit cane may be left at this pruning. The wires of the trellis
should be put up this year, if this has not already been done.

Fig. 33 A and 33 B illustrates the second step in the production of a
fan-shaped head. This form of head is used only for trellised vines
and long-pruned varieties. The formation of the head and the
management of the fruit canes are therefore conveniently discussed
together.



By comparing the pruned vine, Fig. 33 B, with the unpruned, Fig. 33 A,
the method of pruning will be made clear. The unpruned vine shows two
arms, the spurs of the previous year, from one of which have grown
three vigorous canes and from the other two somewhat less vigorous.
The pruned vine shows a complete unit, that is, a fruit cane with its
accompanying renewal spur on the vigorous side and a spur for the
production of fruit wood for the following year on the other side. If
the vine had been more vigorous two complete units would have been
left and one or two extra spurs.

As the form of the vine is determined by the renewal spurs, special
attention should be paid to their position. In this case, the middle
cane on one arm and the lower cane on the other have been used for
renewal spurs. This brings them both to the same height above the
ground and determines the place of the permanent arms. The next year
each of these spurs will furnish a fruit cane and one or two renewal
spurs. The arms will thus in two or three years be increased to four,
or, with very large vines, to six. These spurs should be chosen as
nearly as possible in the plane of the trellis, that is, they should
not project out sideways. Figure 25 shows vines of this kind of full
size and in full bearing.

The fruit canes also should be as nearly as possible in the direction
of the trellis, though this is not so important, as they can be bent
over to the wire when tied up, and in any case they are removed the
next year.

Double-headed vines.

Some growers attempt to arrange the arms of their vines in two stages,
one above the other, forming double-headed or two-crowned vines. The
method is applied to both vase-formed and trellised vines. It is open
to the same criticisms as the vertical cordon, the chief of which is
that it cannot be maintained permanently. The lower head or ring of
arms finally becomes weak and fails to produce wood.

It is easier to maintain in trellised vineyards and has some
advantages, the chief of which is that it makes it easier to keep the
vine in the single plane and to prevent arms getting into the
inter-rows. The double trunk is not necessary and is, in fact, a
disadvantage, as one trunk has a tendency to grow at the expense of
the other.

Vertical and bowed canes.

Figure 24 A shows a long-pruned vine in which the fruit canes have
been tied vertically to a tall stake. This is a method used commonly
in many vineyards. The unit of pruning is the same as in the method
just described, consisting of a fruit cane and a renewal spur. The
framework of the vine consists of a trunk of medium height, with a
vase-formed head consisting of three or four arms. The defects of this
system have been pointed out on page 155.

It is used with fair success with seedless Sultanas and with some wine
grapes such as Colombar, Semillon, Cabernet, and Riesling, in the
hands of skillful pruners. The results with Sultanina are very
unsatisfactory.

By this method, on most of the vines, the fruit canes start from high
up near the middle of the stake, and are therefore too short for the
best results. The canes which start from low down are in most cases
suckers, and therefore of little value for fruit bearing.

Figure 24 B shows a vine with bowed canes. The method of pruning is
exactly the same as in the method just described. The bowing of the
canes, however, overcomes some of the defects of that method. It is
used regularly in many wine grape vineyards of the cooler regions. It
is unsuited for very vigorous vines in rich soil.

Vertical cordons.

In head pruning, the treatment of young vines up to the second or
third winter pruning is identical for all systems. In cordon pruning
the treatment for the first and second is also the same. That is, the
vine is cut back to two buds near the level of the ground until a cane
sufficiently long to serve for the formation of the trunk is obtained.

In the vertical cordon the trunk is three to four feet long instead of
one to two, as in head pruning. This makes it necessary to have a
longer and more vigorous cane to start with. It may require a year
longer to obtain this. That is to say, at the end of the second
season's growth many vines will not have a single cane sufficiently
developed to give the necessary three and one-half feet of
well-ripened wood and properly developed buds. At the second winter
pruning, therefore, it will often be necessary to cut the vine back to
two buds, as at the first winter pruning.



Finally, a cane of the required length will be obtained. The vine is
then formed as already described for the second winter pruning of
headed vines, except that the cane is left longer. When such a vine is
pruned, spurs are left at intervals along the trunk, as shown in Fig.
34. Each of these spurs is a fruit spur and is also the commencement
of an arm. The future treatment of these arms is the same as that of
the arms in head pruning.

Horizontal cordons.

During the first two or three years, vines which are to be given the
form of horizontal cordons are treated exactly as for vertical
cordons, that is, they are pruned back to two buds each winter and the
growth forced by disbudding into a single cane during the summer.

As soon as a well-ripened cane of the required length is obtained, it
is tied to a wire stretched horizontally along the row at from fifteen
to twenty-four inches from the ground.

For this system of pruning, the rows should be twelve to fourteen feet
apart and the vines six, seven, or eight feet apart in the rows. As
the cordon or trunk of each vine should reach the next vine, it will
have to be six to eight feet long. The best shape is obtained when the
trunk is all formed one year from a single cane. It is necessary,
however, sometimes to take two years for the formation of the trunk.
In any case, the cane first tied down should reach at least half way
to the next vine. The following year a new cane from the end of this
should be used to complete the full length of the trunk.

In attaching the cane to the wire, it must be bent over in a gentle
curve and care taken not to break or injure it. The proper form of the
bend is shown in Figs. 27 and 35. Sharp bends should be avoided.


pruning.]

The cane should be placed on top of the wire, but should not be
twisted around it. The end should be tied firmly and the rest of the
cane supported by strings tied loosely in order to avoid girdling when
the cane grows.

In the following spring, most of the buds on a good cane will start.
If the cane is short jointed, some of the shoots should be removed and
only those shoots allowed to develop which are conveniently situated
for permanent arms. If the vines are to be short pruned, the arms
should be developed every eight to twelve inches from a few inches
beyond the bend to the extreme end. For long pruning, the arms should
be farther apart, twelve to twenty inches. Shoots starting from the
top of the cane and growing vertically upwards are to be preferred.

As the shoots develop, the strongest should be pinched repeatedly, if
necessary. This will tend to force the growth of the weaker shoots and
to equalize the vigor of all. At the end of the season, there should
be from five to ten canes growing on each cordon of full length. These
canes are then pruned back to two or three buds, or a little longer
for long-pruned varieties.

During the following spring and summer, the vines should be carefully
suckered and unnecessary water sprouts removed. Any shoots coming from
the lower side of the cordon should be removed early to strengthen the
growth in the shoots on the upper side. Such vines are apt to become
dry or decayed on the upper side. At the end of this year, which
should be the fourth or fifth from planting at the latest, the cordon
will be fully formed and the final style of pruning can be applied. A
short-pruned cordon vine is shown in Fig. 27. The arms and spurs are a
little too numerous and too close together. If this vine required the
number of buds shown it would have been better to have left the fruit
spurs longer and to have left fewer and shorter wood spurs.

The upper vine of Fig. 35 shows a cordon pruned half long. This is an
excellent system for Malaga, Emperor, and Cornichon when growing in
very fertile soil. It gives the half-long fruit canes, which these
varieties need to produce good crops. The fruit canes may be attached
to a wire twelve or fifteen inches above the cordon or bent down and
tied to the cordon itself, as in the lower vine of the figure. The
first method is the more convenient, but the second is necessary where
there is difficulty in obtaining satisfactory growth from the renewal
spurs. When the fruit canes are tied down, as indicated in the lower
vine, renewal spurs may not be needed, as vigorous shoots will
usually be obtained from the lower buds of the fruit canes.

Choice of a system.

In choosing a system, we must consider carefully the characteristics
of the particular variety we are growing. A variety which bears only
on the upper buds must be pruned "long," that is, must be given fruit
canes. It should be noted that many varieties, such as Petite Sirah,
which will bear with short pruning when grafted on resistant roots
require fruit canes when growing on their own roots. In general,
grafted vines require shorter pruning than ungrafted. If pruned the
same, the grafted vines may overbear and quickly exhaust themselves.
This seems to be the principal reason for the frequent failure of
Muscat vines grafted on resistant stock. The cultural conditions also
affect the vine in this respect. Vines made vigorous by rich soil,
abundant moisture, and thorough cultivation require longer pruning
than weaker vines of the same variety.

The normal size of the bunch is also of importance. This size will
vary from one-quarter of a pound to 2 or 3 pounds. It is difficult to
obtain a full crop from a variety whose bunches are very small without
the use of fruit canes. Spurs will not furnish enough fruit buds
without crowding them inconveniently. On the other hand, some shipping
grapes may bear larger crops when pruned long, but the bunches and
berries may be too small for the best quality.

The possibilities of development vary much with different varieties. A
Mission or Flame Tokay may be made to cover a quarter of an acre and
develop a trunk four or five feet in circumference. A Zinfandel vine
under the same conditions would not reach a tenth of this size in the
same time. Vines in a rich valley soil will grow much larger than on a
poor hillside. The size and shape of the trunk must be modified
accordingly and adapted to the available room or number of vines to
the acre.

The shape of the vine must be such as to protect it as much as
possible from various unfavorable conditions. A variety susceptible to
oidium, like the Carignane, must be pruned so that the fruit and
foliage are not unduly massed together. Free exposure to light and air
are a great protection in this respect. The same is true for varieties
like the Muscat, which have a tendency to "coulure" if the blossoms
are too moist or shaded. In frosty locations, a high trunk will be a
protection, as the air is always colder close to the ground.

The qualities required in the crop also influence our choice of a
pruning system. With wine grapes, even, perfect ripening and full
flavor are desirable. These are obtained best by having the grapes at
a uniform height from the ground and as near to it as possible. The
same qualities are desirable in raisin grapes, with the addition of
large size of the berries. With shipping grapes, the size and
perfection of the berries and bunches are the most essential
characteristics. The vine, therefore, should be so formed that each
bunch hangs clear, free from injurious contact with canes or soil and
equally exposed to light and air.

The maximum returns in crop depend on the early bearing of young
vines, the regularity of bearing of mature vines and the longevity of
the vineyard. These are insured by careful attention to all the
details of pruning, but are possible only when the vines are given a
suitable form.

The running expenses of a vineyard depend in a great measure on the
style of pruning adopted. Vines of suitable form are cultivated,
pruned and the crop gathered easily and cheaply. This depends also
both on the form of vine adopted and on care in details.

It is impossible, therefore, to state for any particular variety or
any particular location the best style of pruning to be adopted. All
that can be done is to give the general characteristics of the variety
and to indicate how these may be modified by grafting, soil or
climatic or other conditions.

The most important characteristic of the variety in making a choice of
a pruning system is whether it normally or usually requires short,
half-long, or long pruning. With this idea, the principal grapes grown
in California, together with all those grown at the Experiment Station
on which data exist, have been divided into five groups in the
following list:

1. Varieties which require long pruning under all
conditions.--Clairette blanche, Corinth white and black, Seedless
Sultana, Sultanina white (Thompson's Seedless) and rose.

2. Varieties which usually require long pruning.--Bastardo, Boal de
Madeira, Chardonay, Chauche gris and noir, Colombar, Crabbe's Black
Burgundy, Durif, Gamais, Kleinberger, Luglienga, Marsanne, Marzemino,
Merlot, Meunier, Muscadelle de Bordelais, Nebbiolo, Pagadebito,
Peverella, Pinots, Rieslings, Robin noir, Rulaender, Sauvignon blanc,
Semillon, Serine, Petite Sirah, Slancamenca, Steinschiller, Tinta Cao,
Tinta Madeira, Trousseau, Verdelho, Petit Verdot, Waelcherisling.

3. Varieties which usually require short pruning.--Aleatico,
Aligote, Aspiran, Bakator, Bouschets, Blaue Elbe, Beba, Bonarda,
Barbarossa, Catarattu, Charbono, Chasselas, Freisa, Frontignan,
Furmint, Grand noir, Grosseblaue, Green Hungarian, Malmsey, Mantuo,
Monica, Mission, Moscatello fino, Mourisco branco, Mourisco preto,
Negro amaro, Palomino, Pedro Zumbon, Perruno, Pizzutello di Roma,
Black Prince, West's White Prolific, Quagliano, Rodites, Rozaki, Tinta
Amarella, Vernaccia bianca, Vernaccia Sarda.

4. Varieties which require short pruning under all
conditions.--Aramon, Burger, Chardonay, Chauche gris and noir,
Colombar, Crabbe's Black Burgundy, Durif, Black Morocco, Mourastel,
Muscat of Alexander, Napoleon, Picpoule blanc and noir, Flame Tokay,
Ugni blanc, Verdal, Zinfandel.

5. Varieties of table grapes which usually require half-long or
cordon pruning.--Almeria (Ohanez), Bellino, Bermestia bianca and
violacea, Cipro nero, Dattier de Beirut, Cornichon, Emperor, Black
Ferrara, Malaga, Olivette de Cadenet, Pis-de-Chevre blanc,
Schiradzouli, Zabalkanski.

These lists must not be taken as indicating absolutely for all cases
how these varieties are to be pruned. They simply indicate their
natural tendencies. Certain methods and conditions tend to make vines
more fruitful. Where these occur, shorter pruning than is indicated
may be advisable. On the other hand, other methods and conditions tend
to make the vines vigorous at the expense of fruitfulness. Where these
occur, longer pruning may be advisable.

The more usual factors which tend towards fruitfulness are:

Grafting on resistant vines, especially on certain varieties such as
those of Riparia and Berlandieri;

Old age of the vines;

Mechanical or other injuries to any part of the vine;

Large development of the trunk, as in the cordon systems.

The more usual factors which tend towards vigor at the expense of
fruitfulness are:

Rich soil, especially large amounts of humus and nitrogen;

Youth of the vines;

Excessive irrigation or rainfall (within limits).

In deciding what system of pruning to adopt, all these factors,
together with the nature of the vine and the uses to which the fruit
is to be put, must be considered. It is best when the vineyard is
started to err on the side of short pruning. While this may diminish
slightly the first one or two crops, the vines will gain in vigor and
the loss will be made up in subsequent crops. If the style of pruning
adopted results in excessive vigor of the vines, it should be
gradually changed in the direction of longer pruning with the object
of utilizing this vigor in the production of crop.

This change should be gradual, or the risk is run of injuring the
vitality of the vines by one or two excessively heavy crops.
Finally, each year the condition of the individual vine should
determine the kind of pruning to be adopted. If the vine appears weak,
from whatever cause, it should be pruned shorter or given less spurs
or fruit canes than the year before. On the contrary, if it appears
unnecessarily vigorous, more or longer spurs or fruit canes should be
left. Every vine should be judged by itself. It is not possible to
give more than general directions for the pruning of the whole
vineyard. It cannot be well pruned unless the men who do the actual
pruning are capable of using sufficient judgment to properly modify
their methods for each individual vine.





Next: European Grapes In Eastern America

Previous: Grape-pruning On The Pacific Slope



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