Flowering 2021: So Far, So Good As the 2021 Growing Season Kicks Off

Budbreak gave us the first sign that we were looking at something of a "normal" season this year. Flowering, which began a couple of weeks ago but which has proceeded slowly, confirms that we're still tracking neither notably ahead nor behind what we'd expect, under something close to ideal conditions. Given that we're are roughly at flowering's mid-point, I thought it would be interesting to check on our main red varieties, from most advanced to least. So, starting with Grenache, the only grape on which you can see the beginnings of actual berries:

The Syrah is close on Grenache's heels, looking good, already showing its signature cylindrical cluster shape: 

The Counoise is actually a bit ahead of where I was expecting it. Often late to sprout and flower, in synch with Mourvedre, it appears a little ahead of usual this year:

And finally, Mourvedre, whose flower clusters are formed, but which hasn't yet started to bloom:

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.

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 confirmation for our assessment that 2021 has so far been something very close to an "average" year, 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. For these purposes, we measure the growing season as beginning April 1st. The first 53 days of the growing season (through yesterday) compared to the same dates in past 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
Average 2011-2020	480	2.9	19	1.1
2021	499	2	13	2

So, 2021 has been just a touch warmer than average, but with fewer days above 90 and fewer days that didn't make it out of the 60s than our ten-year average. Two frost nights, but only minimal damage and only in a couple of blocks. That's a pretty solid beginning.

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. It has been dry but a bit breezy over the past couple of weeks. It's too early to know if this has impacted flowering, but we're cautiously optimistic.

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.

So far, so good. Full steam ahead.