You may be asking yourself why are they posting a blog about winter pruning in April? It’s spring for goodness sake, not winter (although the weather hasn’t really reflected the season either). The simple answer is that we’re behind schedule; but of course, we feel the need to rationalize. First, winter (dormant) pruning can take place any time after leaf-fall and before bud-break. Because of our cool wet weather, bud-break hasn’t happened yet – so technically we can still talk about winter pruning. More importantly, winter pruning is really the beginning of the vine’s life cycle. Spring is also a time of new beginnings – and so it makes sense to talk about winter pruning in April. If those two rationalizations weren’t enough, we have a really cute video clip of Mark demonstrating the art of winter pruning (see link to facebook at the bottom), and so the topic for this blog is winter pruning.
Pruning is one of the most important cultural operations in the vineyard and is the most expensive and labor consuming. The goal of pruning is to regulate vine productivity and achieve a balance between yield, fruit quality and vegetative growth (Dr. M. Carmo Candolfi-Vasconcelos, Oregon State University). Balance is critical, not only in our daily lives, but also for our vines. The effects of underpruning (leaving too many buds) may include: a large crop of poor fruit quality, delayed ripening and harvest, and reduced yield the following year. On the other hand, the effects of overpruning (leaving too few buds) may include: a smaller crop, fewer shoots with excessive vigor and possibly shading, and potentially reduced fruit quality due to shading. So, in terms of the vineyard, balanced pruning means leaving just the right amount of buds (not too many and not too few) to produce high-quality fruit with optimal maturity at harvest, as well as ensuring the vine has stored adequate reserves to produce a crop of equal quantity and quality the next season.
There are several formulas and ratios that can be applied to achieve balanced pruning based on the vineyard and variety. One can also simply observe the vine to determine how many buds to retain. The problem with applying either quantitative formulas or qualitative observation methods to achieve balanced pruning is that each vineyard site is different, and usually the vineyard is pruned by a crew of several people working very fast – all with a different level of experience. What we do is prune a small portion of the vineyard ourselves. This way, we can take the time to apply the formulas, observe each vine, and keep accurate records. Over time, we’ll have a better understanding of what “balanced pruning” means in Bjornson Vineyard. Winter Pruning 1001 on Facebook
Next time: more “springy” themed musings.