Budbreak 2024: Right on Time

This winter has continued to follow a pattern something close to the platonic ideal of a Paso Robles winter. Some November rain to get the cover crop started. A cold December, to force the vines into dormancy. Regular and plentiful rain January through March, to keep soil temperatures down, but with sunny and warmer intervals, to encourage cover crop growth. And then a turn in April toward spring-like weather. And as we'd expect, as we passed the spring equinox we've started to see budbreak in our early-sprouting varieties. Below are Viognier (left) and Syrah (right):

The rainfall-by-month graph for the winter so far shows the classic nature of what we've seen:

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, Vermentino, Cinsaut, and Syrah tend to go first, followed by Marsanne, Tannat, and Picpoul, and finally, often three weeks or more after the earliest grapes sprouted, Roussanne, Counoise, and Mourvedre. We've seen budbreak in all the early varieties, but are still waiting even for the middle varieties like Marsanne, which I was surprised to find still fully dormant on a ramble around the vineyard yesterday:

This year is about average for us, significantly later than most of our drought years, though a couple of weeks earlier than 2023. The timing that we're seeing comes despite that we haven't recorded a below-freezing night here at our weather station since February 12th. That budbreak waited some six weeks after our last frost reinforces the importance of wet soils, which hold cool temperatures better than dry soils do. For an overview, here's when we saw budbreak the last dozen years:

2023: First week of April
2022 Mid-March
2021: Last week of March
2020: Last week of March
2019: Second half of March
2018: Second half of March
2017: Mid-March
2016: Very end of February
2015: Second week of March
2014: Mid-March
2013: First week of April
2012: Mid-April

In addition to the variation by variety, there's variation by elevation and vineyard block. Grenache is a good example. I took the following four photos as I walked up the hill. The first photo is from the bottom of the block, where cool air settles at night. You can see the buds swelling, but no leaves yet:

A little further up the hill, you see the first leaves emerging:

At roughly two-thirds of the way up the hill, you see some buds unfurling larger leaves:

And at the top of the hill, nearly all the buds are out:

It will be another few weeks before we see much sprouting in late-emerging grapes like. This is Roussanne (left) and Mourvedre (right), both looking more or less as they would have in mid-winter:

Now our worries turn to frost. Before budbreak, the vines are safely dormant, and a freeze doesn't harm them. But once they sprout, the new growth is susceptible to frost damage. April frosts cost us roughly 40% of our production in both 2009 and 2011 and a May frost cost us 20% of our production in 2022, with Mother's Day marking the unofficial end of frost season. 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. 

That said, there's nothing particularly scary in our long-term forecast. We're supposed to get one more late-winter storm later this week, but it doesn't seem likely to drop below freezing. After that, we're expecting drier weather as the storm track shifts north. 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 2024 vintage.