By: Tom Pierson
Photos: Isabella Cirelli
Striking vine balance is one of the most important achievements in viticulture. Thought is put into it at the outset of vineyard development when considerations of soil type and health, vigor, rootstock, clone, spacing, and a trellis system result in a planting scheme thought best suited for an individual site. Once these decisions are made and the heavy lifting of planting the vineyard has taken place, the vines will soon become fruit-bearing. This is when the annual tasks designed to help reach vine balance come into focus. Second to pruning, shoot thinning or “suckering,” is one of the most important and labor-intensive tasks done each year on the vineyard to achieve this goal.
Above is an illustration of a dormant, cordon pruned grapevine. The two woody arms are the cordons and the knobby spikes, the spurs. Ideally, 2 canes will grow from each spur; called a 2-bud spur resulting in 20 canes per vine and 2 grape clusters per cane.
Let’s take a step back and think about what it means for a vine to be out of balance. A vine can be out of balance for many reasons and some of the more obvious examples are excessive vegetative growth, too much fruit, too little fruit, or some combination thereof. Imagine a canopy that resembles a jungle, overgrown, and unruly. In this kind of environment, mildew might thrive and with all that green growth the vine may fail to put enough energy into cluster formation early on. Simply put; not what we want.
Vine balance is struck when there is the right amount of leaves in the canopy, fruit clusters on the cane, sunlight, airflow, and soil moisture. Suckering is the process of getting rid of excess plant material that would otherwise take away or distract the vine from focusing on the oh so sweet and important fruit. When suckering we remove excess canes (shoots). At our estate, our vines are primarily cordon pruned with 5 spurs on each cordon. With 2 cordons per grapevine that leaves 10 spurs total per plant. Finally (and the last bit of math), at 2 buds per spur, we ideally want to get a total of 20 canes per plant, each cane bearing 2 grape clusters.
Crew members working through and suckering our 777 Pinot Noir in Block 6. This is where our Estate Rose of Pinot Noir comes from!
As mother nature has it, grapevines do not voluntarily produce an even 20 canes per plant. Most often there are far more; somewhere in the range of 10-30 too many depending on the plant and the site. Crews move through the vineyard removing excess shoots by hand. This very detailed work leaves the vine in good condition to deliver great grapes. Not only will the plant be able to concentrate its energy and resources, but the process of shoot thinning also opens the canopy for airflow and sunlight penetration, essential ingredients to vine balance and fruit development. It is in a balanced vine that we can realize the highest quality fruit for our estate wines.
With suckering wrapping up this week at the estate we will shortly move into leaf removal and cane positioning. More to come!