The Kenwood Press
: 02/01/2012

It’s in the buds!

George MacLeod

The most important and expensive practice in the vineyard is pruning. The challenge is to have the vine carry as much fruit as the terroir of our ranch can uniformly mature before the weather turns in the fall. In a normal year, each bud will produce two bunches of grapes. We know the typical weight of each bunch, so we can know just about how many pounds of fruit each vine will produce. The pruner must decide how many buds to leave on each vine – always remembering that each vine is an individual and needs its own personal attention. Too few buds may not reach maximum yield, and too many buds will begin to compete for space and other resources. Getting the entire crop to uniformly ripen at the same time is very important to overall grape quality.

There is more to pruning than assessing individual vine vigor and counting buds. Each bud is a miracle unto itself. This year’s buds were all formed last May and June (2011) and each carries the memory of what the growing conditions were at that time. The rain and weather were difficult at best in spring, 2011, so the buds could be less fruitful. The grower needs to keep that in mind, too, when deploying the army of pruners.

Head pruning provides the lightest touch of all for low bearing vines.
We farm three different varieties at MacLeod Family Vineyard – Sauvignon Blanc, Zinfandel, and Merlot. We think of them as three different children growing up on our ranch, each with their own personality in reacting to our terroir, and indeed “talking” to us about it. This will be our 32nd harvest and I admit it has taken all these years to really understand vine language. The whole secret to growing grapes into great wine is to listen, and fine-tune the practices so that each child gets the personal attention it needs to thrive.

When we began growing here 32 years ago, we pruned all the vines the same way. But as the years passed, we continued learning and we began to experiment. Now we prune each variety differently. It turns out that successful pruning of Sauvignon Blanc has a lot to do with the management of sunlight on the developing bud.

Cordon pruning requires a trellis to handle the extra weight.
We began with cordon pruning for our Sauvignon Blanc. This type of pruning is the simplest, most economical, and easiest to teach. It worked well with good quality and respectable yields. But after some 15 years, the yield began to decrease and the buds became less fruitful. Close examination during the growing season showed that many of the buds that grew last summer were barren or had only one bunch each instead of the typical two.

An exmple of cane pruning. Note the long canes left on each cordon
We are now converting all our Sauvignon Blanc to cane pruning. With this method the individual buds are exposed to sunlight all summer. We feel that this extra sunlight makes the buds more fruitful. This method is more expensive and requires a higher level of training for the pruner.

Zinfandel tends to over produce. Plus the bunches are sensitive to sunburn and bunch rot. It turns out that with cordon-style pruning Zinfandel bunches are often exposed to too much sun and frequently the bunches overlap on each other to make them more vulnerable to bunch rot. Here we have history to help us. All the great 100-year-old Zinfandel vineyards are what we call head-pruned. By this method, the vines are pruned to look like a three foot diameter bush. The vine is pruned to assure nice spacing of the productive new buds around the vine. The bunches are then nicely spaced under the canopy with no overlap or touching and at the same time lots of air and dappled sunlight. Winemaker Mike Lee years ago told me, “George, I have made Zinfandel wine for 20 years using both head-pruned and cordon pruned grapes, and the head-pruned Zinfandel is best. But I think this is probably caused by the fact that the head pruned vines usually carry a smaller crop.”

Our Merlot does not seem to be bothered by how we prune it. But it has another problem. It is very sensitive to bad weather at bloom time and often bears a small crop (a characteristic that has led some growers to refer to Merlot as “Mer-little.”) Recall that grapes are self-pollinating so a good crop set depends on decent weather during bloom. But Merlot is just more sensitive.

My purpose in this discussion is not to teach you to prune. There are dozens of text books on the subject already. I wanted you to know that when you see a dozen pruners out in the vineyard on a cold winter day, understand that they are dealing with some sophisticated cultural techniques that have a real impact on the quality of the wine that ends up in your glass.

Finally Some Good News

After years of falling grape prices with a number of growers having to sell below cost, or not find buyers for their fruit at all, the worm is beginning to turn. Demand for grapes is now rising, and with it an improvement in prices. This has been a long time coming. The past several years have been difficult for county grape growers and you can find a smile or two on grower’s faces. And to our loyal readers, we begin our tenth year of Journey to Harvest with our hopes and optimism still intact.