Pruning calls for some
thought. A shoot will grow 6m (20ft) in a single
season, and every eye along the entire length
is capable of bearing a shoot which will produce
one or more bunches of grapes. In addition, a
vine is able to bear fruit on the older wood,
though this would prove too much for its constitution.
If new shoots are encouraged, the eyes on the
old wood will not be sufficiently vigorous to
bear fruit, and the fruit on the new wood will
There are two main methods of pruning, the long
rod system and the spur system.
The long rod system – This name applies
when one or two new shoots or rods are allowed
to grow on and all other growth is restricted.
With vines, pruning is done in the depths of winter,
the first days of January, before the sap begins
to rise, being most suitable. For greenhouse plants,
allow the vine to form two stems or rods; train
these as far apart as possible and tie in to wires
stretched across the roof. The rods will grow
6m (20ft) or more their first year. On New Year’s
Day, cut the weaker rod back to two buds near
the base. On the other, stronger stem will be
borne the season’s crop, and the stronger
stem from its two buds will be grown on to produce
the crop for the season after that. To prevent
the formation of too much foliage, pinch back
all laterals to two buds – one to bear the
fruit, the other the foliage, which should be
stopped at two leaves. Do this pinching back of
laterals in summer over several weeks so as not
to check the plant too drastically.
During the first year, no vine should be allowed
to fruit, and the following year only one bunch
from each lateral should be retained.
Should it happen that buds on the lower part of
the rods refuse to come into growth, lower the
rod from the roof for three or four weeks before
tying it in again. This will persuade the lower
buds to ‘break’ whilst retarding the
upper buds at the same time. For vines in the
open, growing vertically, follow the single rod
and spur system, retaining the strongest shoot
of two basal buds to bear fruit. Then, after fruiting,
cut back to a single eye or bud to produce next
The spur system – From the rod which has
grown away unchecked, select alternate buds on
each side of the stem to produce short laterals.
These bear fruit and should be stopped one leaf
beyond. Then cut back each shoot to two buds in
winter, one of which will form the grapes, the
other the foliage. This will build up a system
of spurs. Stop fruit-bearing laterals at the first
joint after the bunch has formed, and pinch back
non-fruiting laterals to 5cm (2in).
Vines growing horizontally against a wall should
receive the same treatment as espalier pears.
Cut back to the lower three buds in winter, the
upper forming the extension shoot whilst the lower
buds, one on either side of the stem, will form
the lower arms. Train them first at an angle of
45°, tying them to canes, and then gradually
bring them to the horizontal position. The following
year, cut back the extension shoot again the three
buds, the two lower ones facing in opposite directions
to form the next pair of arms, about 40cm (16in)
above the lower pair and so on until each vine
reaches the required height. Each arm or rod should
be treated the same as for the spur system.
When the fruit has set it must be decided how
many bunches the vines can mature. This depends
upon age. Probably the rods will carry ten bunches
in their second year, twice that number next year
and so on. Should there be overcrowding, nip out
a few grapes with pointed scissors, as well as
any damaged fruits.
Where growing under glass, a moist atmosphere
is necessary for the buds to ‘break’.
Syringe the vines daily to keep away red spider.
This should stop when the fruits have formed and
begun to show colour, otherwise they may decay.
At this time, give ample ventilation so that moisture
does not remain on the fruits. The grapes will
be ready in late summer and early autumn.