Flowering 2023: So Far, So Good
May 23, 2023
This past weekend was the Paso Robles Wine Festival, our unofficial end to frost season. It was lovely and warm, and I dove into our pool as soon as I got home. And yet most of the questions that I got from guests at the festival were about our winter, along the lines of "how did you withstand the crazy rains this year?". That's a good reminder of the slow dissemination of news, as well as the staying power of striking video images. But we're well into the growing season, and things are moving fast in the vineyard. And so it was with anticipation that I took a walk around the vineyard yesterday afternoon. When I got to the top of our tallest hill, I found flowering in our Viognier:
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. From this point on, if the berries are fertilized successfully, they'll grow in size and mass until veraison, at which point they stop growing but accumulate sugar and ripen the seeds within. 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, as much as a month after the early grapes, Roussanne, Counoise, and Mourvedre bring up the rear. And there is variation between vineyard blocks as well, with cooler, lower-lying areas a week or two behind the same grapes at the tops of our hills. The only other grape that I could find flowering in was Grenache from another top-of-hill block:
Flowering marks 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 provides more support for our assessment that 2023 is looking like something of a throwback year, more like what we saw in the 2000's and early 2010's than what we've seen most of the last decade. Since the beginning of April we've had an above-average number of frost nights and days that don't get out of the 60s, and a roughly average number of days that top 90°F, and a below-average number of growing degree days (a rough number of hours that are warm enough for the grapevines to photosynthesize). The first 52 days of the growing season compared to the same dates the past dozen years:
| Year | Degree Days | Days > 90°F | Days < 70°F | Nights < 32°F |
|---|---|---|---|---|
| 2011 | 383 | 0 | 24 | 4 |
| 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 |
| 2022 | 554 | 6 | 13 | 3 |
| Average 2011-2022 | 488 | 3.1 | 18 | 1.3 |
| 2023 | 470 | 4 | 21 | 4 |
As always, though, the devil is in the details. It was so chilly the first quarter of 2023 that the frost nights we saw this April came with low-lying vineyard blocks still dormant and therefore not at risk. That's great. The 90+ days were only barely into the 90s (top temperature: 93°F) and in every case the low the following night dropped into the 40s. That's great too. So the vines have had a good runway to catch up a bit after their late start, and in our estimate they have. From the roughly three weeks later than normal that we saw 2023's budbreak, we've probably made up half of that deficit.
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 we saw flowering begin the second week of May, we're likely to be enjoying the intoxicating scent of bloom until the sometime in mid-June.
What do we want now? We're hoping 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. The Paso Robles weather forecast suggests that we're entering a little cooldown that should last us through the work week, and then temperatures returning to normal levels in the upper 70s and low 80s by this coming weekend. There is no rain expected, or any unusual wind. That bodes well.
So far, so good. Full steam ahead.