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PRUNING 101: down to brass tacks

by David on March 21, 2008

In the last post Nancy, our Director of Education, recapped our staff “Pruning 101″ session. It was a great morning – everyone caught on really well and it was a bloodless coup – no trips to the emergency room! The vines seem to be OK, too. 😉 Anyway, Nancy asked me to tell you a little bit about what I’m trying to accomplish by pruning.

I’m always sorry to see the end of pruning season because it’s great quiet time out there, just me and the vines. But – the buds are swelling. It’s time to finish so the vines don’t waste any of their energy on growth that’s just going to be pruned off later. So, here goes:

When: Any time from December through February. Once we’re sure the vines are dormant, we can start and it’s important to finish before the growing season starts again (bud-break), usually mid-March. I did the Merlot and Cabernet Franc first, because they usually bud out ahead of the Cabernet Sauvignon and Petit Verdot. Pruning at the last minute, like this, is great, when I can swing it, because it may delay bud-break and cut down on the number of nights I spend up, worrying about frost.

How: The vines need to be severely pruned, kind of like roses. From a wild tangle of shoots that are 3-4 feet long, I bring it down to what looks like almost nothing – just the vine “skeleton”.

Our vines are trained into what is called a bi-lateral cordon (two permanent arms) and we use what is called vertical shoot positioning (VSP), which means the shoots grow vertically up through the trellis wires. VSP maximizes light exposure to the leaves, which helps heighten fruitiness, and provides filtered light to the clusters.

I leave several small protrusions on the cordons, called spurs. The spurs contain the buds (growing points) for the next season’s shoots. The theory is that for each bud I leave, I’ll get a new shoot in the spring. From each new shoot, I can expect about two clusters.The problem is that the vines don’t read the textbook, and I’m bound to have some surprises. So, I’ll go through in April, to see what actually happened, and inevitably do some shoot thinning. If there are too many shoots and the canopy is dense, it blocks the light and increases mildew and mold problems. Plus the excess shoots produce excess clusters, which can compromise quality.

In late May, after flowering, I’ll make cluster counts to see if I need to do some thinning. There’s nothing I can do about too few, but If there are more clusters than I anticipated, the grapes may not ripen properly and could lack flavor intensity.

Every year is a new ballgame, but one thing we know for sure: Quantity and quality hardly ever go together, when it comes to wine, so pruning and thinning carefully is critical to the quality of the vintage.

Now, we wait for the new growing season to begin and pray we don’t have too much frost this spring!

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