michael wrote:

I have absorbed though not completely understood
all of the advice I have received on this group
recently.This week (first week in July in
England) I have been hedging my 35 vines for the
first time this summer.They are on Double Guyot
which involves renewal cane pruning.My main
query in my recent mails is how to prevent the
mass of growth which develops in mid summer,and
so preventing air and spray get thoroughly to
all parts of the vines.Just to be sure what I
mean,I will try to explain clearly and without
diagrams what the problem is. 1)The Double Guyot
system,widely used in England and
Europe,involves removing most of the vines
growth each winter,and leave two horizontal rods
which start near the top of the old 15" high
thick base.These rods are each about 2 foot long
and stretch right and left along wires.From each
rod about 7-8 buds are selected-some buds are
double or triple and I reduce these to a single
bud. In early summer these buds break and
produce rapidly growing vertical canes.Most
canes produce flower and fruit around 2 to 2.5
feet from the ground.In addition there is
vertical growth near the centre which is used
for the following year's rods. 2)Each of the
vertical canes grows quickly to the top wire at
5.5 feet,when they are 'hedged'.Along these
vertical canes,buds and leaves are produced at
about 6"-8" intervals,and in the angle between
the buds/leaves and the cane,sideshoots appear
at 45 degrees.It is these sideshoots that cause
the problem of growth.I am never sure whether to
remove them initially in June when it is easy,or
only remove the badly placed ones later when
they will inhibit grape development. 3)It does
not seem clear to me whether these sideshoots
have a clear function, either to support grape
development or feed next years buds on the
vertical canes chosen for next years horizontal
rods. 4)On this latter point,I have noticed that
my newly planted vines are much more fruitful in
their early years than later.Could this be
because when initially producing the first
rod,one is encouraged to remove sideshoots from
its vertical growth-it is then bent horizontally
to produce a first (single Guyot) crop.This
strongly suggests to me that sideshoots are not
required to support the next years fruit bud
development. 5)So my current thoughts are to
remove sideshoots from the renewal vertical
canes,but keep them on the vertical canes
carrying this years fruit.I have seen in one
article that these sideshoots should be pruned
to two leaves,which might be a compromise.

I hope I have described the problem more clearly
than before,and I am surprised that this massive
growth problem created by these sideshoots is
not discussed more in the literature.
Cheers,Michael

Michael, I have read in the literature is the
number of leafs required to ripen fruit. It seems
that shoots of approximately 4 feet in length are
the ideal length and the ideal number of leaves.
(California trials, I believe) Longer shoots
actually seem to be detrimental to fruit quality
according to an article I read. But, like you
said, I do not know if the leaf count included
the leafs in the laterals. If my laterals are
causing shading or a dense canopy, I remove them,
otherwise I leave them. There is often articles
about research in this area and more about
viticulture research in general in the
publication "Practical Winery & Vineyard" Their
website is www.practicalwinery.com

Here is one from this link that specifically
addresses the question and it seems that it
"depends" on several factors including the vigor
of your vines, canopy shading etc etc:

http://www.practicalwinery.com/sepoct01p5.htm