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