This winter has been wonderful. We've accumulated nearly 31 inches of rain, without a single storm that caused us damage, flooding, or even any notable erosion, thanks to an amazing 62 days with measurable precipitation. The green of the cover crops is mind-bending. And it's been chilly enough that the vines have been kept dormant. Our weather station at the vineyard has recorded 29 below-freezing nights, and we've had weeks at a time where the days have been cold too: we had a 39-day stretch between January 31st and March 10th where it rose into the 60s just three times, including several days that topped out in the 40s. That's unusual. But the net result has been that we've been largely free of the worries of recent years that the vines might sprout prematurely, leaving them susceptible to damage from a late frost.
The last two weeks have felt different. Our last below-freezing night was March 14th. Since March 15th, we've seen six days reach the 70s, surpassing the total between December 1st and March 14th. The lengthening days and the warm sun have produced a wildflower bloom that's getting national media attention. And the vines have begun to wake up:
Budbreak, as you probably guessed from the name, is the period when the grapevine buds swell and burst into leaf. It is the first marker in the growing cycle, a point when we can compare the current season to past years. Upcoming markers will include flowering, veraison, first harvest, and last harvest. And like harvest, budbreak doesn't happen for every grape simultaneously. Early grapes like Viognier, Grenache Blanc, Grenache, and Vermentino tend to go first, followed by Syrah, Marsanne, Tannat, and Picpoul, and finally, often three weeks or more after the earliest grapes sprouted, Roussanne, Counoise, and Mourvedre. And it really is just starting. I only saw signs of budbreak in Grenache (pictured above), Grenache Blanc, Vermentino, and Viognier (below):
This year is later than many years this decade, and a month later than our record-early 2016, but it's only about average for what we'd have expected historically. When we saw first budbreak the last dozen years gives a good overview:
2018: Late March
2016: Very end of February
2015: Second week of March
2013: First week of April
2011: First week of April
2010: Last week of March
2009: Second week of April
2008: Last week of March
2007: First week of April
It's important to note that the vast majority of the vineyard is still dormant. I was only able to find leaves in our earliest-sprouting grapes and only at the tops of the hills, which are warmer than the valleys, where cold air settles. It will be at least another couple of weeks before we see sprouting in late-emerging grapes like Mourvedre or Roussanne, or in low-lying areas. This Mourvedre block is one of many that show no signs of sprouting yet:
Why does budbreak happen when it does? It's mostly a question of soil temperatures. Grapevines (and all deciduous plants) are cued by rising soil temperatures to come out of dormancy and begin their growing season. Evolutionarily, plants are trying to balance competing goals: to sprout early enough to achieve maximum carbohydrate generation from photosynthesis, while staying dormant long enough to avoid suffering damage to their reproductive prospects through frost.
Bud break varies with the winter. Because wet soils retain cold better than warm soils, winters that are both wet and cold tend to see the latest emergence from dormancy. The consistent cold and wet we received in the winter of 2018-2019 meant that despite the lengthening days, the vines' most important sensors were telling them that winter was still in effect, and sprouting would be a risk. And, in fact, budbreak does begin our white-knuckle season, since while dormant vines can freeze without danger, new growth is susceptible to frost damage. April frosts cost us roughly 40% of our production in both 2009 and 2011, and we don't feel truly safe until mid-May. So, we've still got more than a month to go before we can relax, and I'm thankful that it will be a few weeks before our later-sprouting varieties and our lower-lying (read: more frost-prone) areas are out enough to be at risk.
But in general, if you could design a favorable winter weather pattern, it would look a lot like what we've seen recently. We'd ask for regular frosts and rain through the middle of March, and then a switch to a warm, dry pattern thereafter. While we're always grateful for rain, since frosts tend to follow in the wake of frontal passages, the precipitation you get in spring storms isn't worth the risk of frost damage. We've been fortunate that the recent storms we've received have largely been warm ones, without frost, and that the extended forecast doesn't seem to contain anything particularly threatening. But there's a long way to go.
Meanwhile, we'll enjoy the rapid changes in the vineyard, and the hope that always comes with the emergence of new buds. Please join me in welcoming the 2019 vintage.