Flowering and Fruit Set Provide Reasons for Optimism After a Challenging Beginning to 2022
June 03, 2022
At the beginning of the growing season, no news is usually good news. If you avoid frost, and avoid cold or wet or windy weather during flowering, you can expect to see fruit set (when the berries start to form) roughly two months after budbreak. And in the sections of the vineyard where we avoided frost, that's what we're seeing. This Syrah vine is a good example:
2022, however, has not been a news-free spring. I wrote a couple of weeks ago about our frosts. And though most of the vineyard avoided dropping below freezing, it got cold everywhere, which has lesser but still important impacts on the vines' ability to fertilize the flowers and turn them into grapes.
Flowering and fruit set mark the rough quarter-pole of the growing season. There's a lot more year to come than in the rear-view mirror, but it's still a point at which you can start to make comparisons to other vintages. Doing so highlights the extent to which 2022 has so far been an outlier, at least compared to the past decade. Some of the data points we measure are growing degree days (a rough number of hours that are warm enough for the grapevines to photosynthesize), the number of days that top 90°F, the number of days that don't get out of the 60s, and the number of frost nights where temperatures bottomed out at or below 32 at our weather station. The first 53 days of the growing season (April 1st - May 23st), through the third weekend of May which we usually take as the unofficial end of frost season, provide a good marker. Here's how 2022 compares to past years:
Year | Degree Days | Days > 90°F | Days < 70°F | Nights ≤ 32°F |
---|---|---|---|---|
2012 | 496 | 5 | 15 | 3 |
2013 | 615 | 9 | 12 | 1 |
2014 | 553 | 5 | 16 | 0 |
2015 | 378 | 0 | 26 | 0 |
2016 | 494 | 2 | 14 | 0 |
2017 | 517 | 6 | 17 | 0 |
2018 | 454 | 0 | 21 | 1 |
2019 | 410 | 0 | 25 | 0 |
2020 | 500 | 2 | 20 | 2 |
2021 | 499 | 2 | 13 | 2 |
Average 2012-2021 | 491.6 | 3.1 | 17.9 | 0.9 |
2022 | 554 | 6 | 13 | 3 |
You can see that 2022 has been a bit warmer than average overall, but the devil is in the details (and the frost nights). We had two of our 90+ days in early April, which meant that things were far enough out that the April 12th and 13th frost nights had more impact than they might have in a cooler year. And the other frost night on May 10th was so late that everything was out far enough to take some significant damage, and the four chilly, windy days that preceded it, none of which got into the 70s, were in a position to impact flowering in our early varieties.
During flowering, you hope for consistent, sunny weather, with only limited wind and no rain. Cold, wet, or windy weather at this stage can produce incomplete fertilization, or shatter, where a cluster has a high proportion of unfertilized berries, looking snaggle-toothed and (often dramatically) reducing yields. Some varieties, most notably Grenache, are prone to shatter, while others are less so. So it wasn't a shock that when I explored our Grenache blocks I found evidence of shatter:
Is this a catastrophe? No. A little shatter in Grenache can actually be a good thing, because it opens up the clusters and means we don't have to do as much fruit thinning on this famously productive grape. And that seems to be the degree we're seeing, with impacts in the 20%-50% range. It's additional good news is that I couldn't find any evidence of shatter in anything else.
Flowering is the second of the four viticultural markers that we use each year as markers: notable reference points that indicate where we are compared to other years. These are, in order:
- Budbreak (typically beginning late March or early April, and lasting three weeks or so)
- Flowering (typically beginning mid-May, lasting a month or so)
- Veraison (typically beginning late July or early August, lasting as much as 6 weeks)
- Harvest (typically beginning late August or early September, lasting two months or so)
You might notice that in the above list, the duration of each stage is longer than the previous one. That's because grapes start their growing cycle at different times, and also proceed at different rates. So, harvest stretches over a longer time than veraison, which takes longer than flowering, which takes longer than budbreak. Given that we saw flowering begin the second week of May, we're likely to be enjoying the intoxicating scent of bloom for another couple of weeks. Our late-sprouting varieties like Roussanne are still in peak flowering:
If you haven't seen grapevines flowering before, you can be excused for finding it underwhelming. It's not a showy process. Still, the tiny white fuzz-like flowers that appear on the clusters are the first stage of development of the berries. As with all parts of the vineyard annual cycle, there are grapes that enter (and exit) flowering earlier and later, with the early grapes being Viognier, Grenache, Grenache Blanc, and Vermentino. They are followed shortly by Marsanne and Syrah, and finally, weeks after the early grapes, Roussanne, Counoise, and Mourvedre bring up the rear. We might not know where everything is going. But for our early grapes, like the Viognier below, things are well on their way.