As we make our way into Spring, the vineyard comes alive with beautiful young green buds. This period is known as budburst or budbreak, triggered by the rise in temperature, it is the first sign of new life after their winter dormancy. However, before we delve further into budburst, it’s important to understand the role of the winter dormancy in even budbreak.
To achieve maximum winter dormancy the vines need to gather a required number of cold units or chilling hours. It varies between cultivars but is usually several hundred hours below 10°C. If the winter period is too warm, and the number of cold units too few, the vines react like most people do after a terrible night’s sleep – tired and a little confused. This ‘confusion’ can lead to uneven bud break – where some vines are still sleepy and dormant, while others are coming to life with new growth. As the vines continue to bud and grow, the ones that had an earlier start will grow stronger, while the sleepier one lag behind.
This uneven growth pattern will then persist through to harvest, ultimately leading to uneven ripening. In extreme cases, this can lead to some vines forming berries while others are still flowering – and may even lead to the same block needing to be harvested twice at two different intervals.
If there are signs of uneven bud break, Christo and the team manage it through a tip-action: they remove the tips of the vines that broke early, slowing their growth for a few days and allowing the later-breaking vines time to catch up. These interventions help even out the growth rate between the buds, and ensures uniform growth as the vines approach flowering, cluster set, ripening and ultimately harvest. This winter, our vines enjoyed plentiful cold units and a proper dormancy, resulting in even budbreak throughout most of the vineyards.
