Pruning is one of the most important and most neglected practices in home
plantings of grapes. Grapes need some form of support, and pruning
(training) is necessary to develop the plant and to maintain it on the
support provided. Regular, purposeful pruning is essential for controlling
the number, position and vigor of fruiting canes and the yield and quality
of the fruit.
Grapes should be pruned during the dormant season, late November to March.
Since winter injury of fruiting canes will occur to some extent, late winter
pruning generally is preferred. If pruning is delayed until near bud swell,
the cuts commonly ooze sap abundantly. Though not desirable, "bleeding"
seems to be of minor importance.
Pruning at planting time
The best cane usually is selected and shortened to two buds. All other canes
Sometimes a plant is especially vigorous and has one cane that will reach
the lower wire or beyond. In this case, the cane may be cut at the height of
the lower wire and tied tautly to it. When new shoots are about 1 inch long,
remove them except for the upper two or three near the wire. De-shooting is
illustrated in Figure 4. From among the shoots allowed to develop, one will
be selected to complete the trunk.
Select the most vigorous cane and remove all others. If the cane is long
enough to reach the top wire, cut it off at that height and tie tautly to
the wire (Figure 5a). A shorter cane would simply be pruned and tied to the
lower wire ( Figure 5b). Plants having no canes long enough to reach the
lower wire should be pruned as a newly set plant (one cane shortened to two
Early in the second growing season, some cane selection for the next year
may be possible on the larger, more vigorous plants. When new shoots are 1
to 3 inches long, remove all but three or four arising from near each wire.
Flower or fruit clusters are best removed as noticed. Plants bearing no
fruit make stronger vine growth.
In the dormant period preceding the third year, the more vigorous plants
should consist of a main stem or trunk reaching to one or both trellis wires
and having several canes. Considering position and vigor, select two of the
best canes at each wire and remove the others. Shorten the selected canes
leaving two to four buds on each. See Figure 6.
Plants pruned and tied to the lower wire in the second year may be pruned as
in Figure 7.
Plant pruned and tied to lower wire in previous year -- (a) unpruned; (b)
after pruning; (c) long cane tied to upper wire completing development of
The two to four buds left on the short canes will give rise to shoots that
will bear some fruit. They also will be the source from which to choose next
year's fruiting canes.
Beginning in the fourth season, the plant should have two or more canes
extending in both directions at each wire. Select a fruiting cane and where
possible a renewal spur at each of the four arms. Figure 8 illustrates a
typical plant before and after pruning. Note that renewal spurs were chosen
from canes nearest the trunk. This is important for maintaining fruiting
wood close to the trunk and keeping the whole plant within its allotted
space. Where this is not practiced, the fruiting wood develops farther from
the plant each year, crowding adjacent plants and weakening growth.
Select the fruiting canes with the following considerations in mind:
moderate vigor (diameter and length), reasonably straight, originating near
the trunk, and reasonably close to the appropriate trellis wires. All other
growth is removed, including any sucker growth arising on the lower trunk.
Shorten the selected fruiting canes leaving six to 10 buds. Leave more or
fewer buds depending on plant vigor -- 10 to 12 buds on vigorous plants,
four to six on weaker plants.
In the following years, pruning will not be greatly different from fourth
year pruning. Where a renewal spur was present during the preceding growing
season, it is frequently the nearest source from which to select a fruiting
cane. Thus, the old arm with numerous canes attached can be removed with one
cut made near the trunk. If no renewal spur is present, select a cane
elsewhere and if possible, leave a spur for use the following year.
The number of buds left per cane may be increased to about 10 to 12 on
plants of good vigor. Again, number of buds left should be adjusted
according to plant vigor.