A dry spell?

A really, really long spell.  As of the 17th of January California Governor Jerry Brown declared a drought emergency for the state, saying that the state is facing "perhaps the worst drought that California has ever seen since records (began) about 100 years ago."  It has indeed been very dry and warm, 75° F today in Oakville, and we haven't had any measurable rainfall since the 6th of December.  Even so, I think the Governor will find plenty of northern California water to send to the southern end of the state.  Ho hum.
Now whilst I am loving this fantastic, but unseasonable weather, I understand that California is a rather dry place - even on a normal rainfall year - and we do need some rain to fall.  In many vineyards, no doubt, soil moisture content is at an all time low, and warm temperatures could mean an earlier than normal budbreak, especially in some white grape varieties.  Yesterday an owner/management company, of a vineyard on the Oakville Crossroad, decided to take matters into their own hands and water their vineyard.  The sprinklers sprinkled all day, were still sprinkling when I left work, and were still sprinkling when I arrived at work this morning.  The ensuing winter wonderland of icicle-laden grapevines was the result of the overnight temperatures dipping below freezing.  It looked fantastic, but I bet it used up a lot of water.

Kicker canes.

Pruning in the Napa Valley is in full right swing now.  I hope to begin pruning Vinoland's black grape varieties today or tomorrow. Vinoland is very fortunate not to have an issue with high vigour in the vineyard.  The vines here are rather well balanced individuals, in part due to the fact that they are head trained and in some part due to the fact that our soil is lousy. Except for one small area that is.  In that particular location the vines are planted a little closer together, one row is cordon trained and, seemingly, the vines have found something particularly appealing to them beneath their roots - so they misbehave.  But, what if high vigour was an issue here, as it is on the highly fertile valley floor?  What could be done to suppress the vigour in the vines at the onset of their annual growing cycle? Planting a cover crop could be one solution, but another approach would be to leave kicker canes on the vines.
A kicker cane (aka a sacrificial cane or a vigour diversion cane) can be very helpful in controlling overly enthusiastic vines. This method involves retaining supplemental, disposable canes at pruning time - at the crown of a head trained vine, or at the apical end of a cordon trained vine.  In the cordon trained vine, a kicker cane takes advantage of a grapevines natural disposition towards apical dominance and can also aid in delaying budbreak. Increasing the number of buds retained per vine has an overall vigour reduction effect as the kicker cane becomes a sink for new growth.  Later, after budbreak, the entire cane will be removed to ensure it doesn't sap too much of the vine's vigour.  In the photograph above it is clear that when the kicker cane is removed only the desired 2 bud spur, on this old quadrilateral-cordon trained vine, will remain.
Okay, that's enough of that, I'm off outside to prune!