There is a lot of information available about vine pruning. Most of it focuses on technique and philosophy. I would like to address more practical aspects by outlining how we organize the winter logistics of pruning at Hardscrabble, Linden’s home vineyard.
Every operation is different in terms of labor and size. At Hardscrabble we have about 20 acres of vines. Four of us do the pruning, but we are also responsible for many other aspects of the business. Over the years our seasonal pruning strategies have evolved in order to adapt vine needs to time constraints.
In a perfect world I would wait to do all the pruning in March and April when the sap is flowing (known as bleeding or crying depending on where you are from). At this time there is less trunk disease pressure and one cam more easily evaluate any winter damage. It’s also more pleasant weather for the pruner to work in.
In the real world we have to get started much earlier in order to get the job done before bud break. Additionally, Linden has a full time staff that shows up every morning at 7:00 ready to work. So we compromise and start pre-pruning around Thanksgiving. I try to balance the realities of running a business while respecting the health of my vines.
With the exception of some Merlot blocks, Hardscrabble is cane pruned. I only mention this because in a logistical sense it means that pre-pruning can only consist of removing the top third of the canopy, which is accomplished fairly quickly. By mid-December we are in a position where the final pruning needs to commence.
Three factors prioritize the pruning sequence: 1. Vine hardiness to winter damage and wood disease: Vidal, Riesling, Petit Manseng, and Petit Verdot are first up to bat. 2. Vine age: Older vines first, non-bearing last. I see more winter damage and die back in one- and two-year old vines. I also worry about wood diseases when making so many cuts along the forming trunk near the base of the vine. 3. Block importance: our best performing blocks are given top priority (pruned later in the season).
[As a side note, last year I did a trial on the effects of pruning timing on bud break timing. Starting in December I pruned two different rows of Cabernet Sauvignon from a homogeneous block every three weeks. The last two rows were done in April (the vines were still dormant). There was no difference in bud break times. This confirmed my theory that late pruning delays bud break only when it is done after the distal buds have begun to show bud swell or even bud break.]
We approach each block as an individual. Before we start, I walk every row and prune any non-uniform vines. This mostly consists of re-plants. I cut them back very hard, much more severely than if the same vine was part of a newly planted block. Re-plants need at least twice as many years to come into production because of competition from neighboring established vines. It is human nature to be optimistic. My staff has been pruning these vines for years, but I would always find young replant vines struggling, burdened by excessive yields and meager shoot growth. I find that brutally aggressive pruning is the best way to address the problem. I’ve found that cutting a vine back severely is not an emotionally easy task for most people. So it has become my job.
When I am making this first pruning pass I am also getting a feel (and reminder) for last year’s vigor. As a group we talk about specific strategies for the block. This usually involves discussing the proclivity of renewal spurs and cane length.
Renewal spurs are a necessary evil when cane pruning. I don’t like them because they tend to produce larger, more vigorous shoots that interfere with the goal of uniformity. In many cases they are essential in order to retain and maintain vine form. I find that it is human nature to leave too many than is necessary making for a crowded head area.
Varying cane length is our way of commutating and adjusting for individual vine size, vigor and capacity. The only time one can evaluate a vine’s growth and potential capacity is before it is pruned. The pruner is trained to evaluate last year’s growth by observing the number and size of canes that grew last year. A healthy, productive vine will be pruned to two full-length canes. Weaker vines are pruned to shorter canes or just renewal spurs. The system will communicate an individual vine’s potential to the person doing the shoot thinning (less shoots left remaining on shorter canes) and cluster thinning.
My own pruning priorities focus mostly on young vines that are entering their third, fourth and fifth years. This is the stage where the foundation of the vine’s structure will be determined for the life of the vine. As I have become more experienced I have seen the advantage of pruning back fairly severely in this stage.
Pruning was my first vineyard job back in 1979. I still vividly remember standing in snow with a cold wind howling and loving every minute of it. I knew immediately that I was to become a winegrower for life. My enthusiasm for pruning has only grown. The satisfaction and creativity of shaping and renewing a vine never wanes.
Grape Press, January 2018