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