Technically speaking, grapevines are perennial plants, which means that they bloom in the spring and summer, then die back in fall and winter, finally growing again via energy stored in their rootstock the following spring. If left to do their own thing, grapevines grow to a thick mess of leaves and branches, which is why it is so important to keep things in check by constantly paying attention to its needs encouraging its potential to produce fruit.
The following is a step by step of what the vine goes through annually in its varying stages of the life cycle:
Once leaves begin to fall post-harvest all the way to the spurring of growth in spring, grapevines are laying dormant and resemble dry woody twigs. With very little activity within the plant happening in the winter, one might think there’s not much to be done. However, a winemaker knows that pruning is required to cut back the previous year’s canes, leaving only the best canes to grow new shoots.
2. Bleeding and bud break
The transformation begins in early spring, when sap exuded by the pruning cuts, AKA bleeding, occurs and is the vine’s announcement that the onset of bud break is coming. The first buds are incredibly delicate, which is why spring frosts can be so devastating in the vineyard.
3. Shoot and leaf growth
Newly emerging shoots grow rapidly as temperatures warm up, so paying attention to their spacing and directional growth potential is extremely important. Depending on the situation, the winemaker will have pruned the downward-facing shoots to ensure that all of the new shoots grow upwards. This practice reduces the crop size while increasing the potential quality of the fruit, as a vine that produces fewer grapes will likely make more concentrated grapes. At this time in the cycle, frost remains a risk and can cause the shoots to return to dormancy.
4. Flowering and fruit set
As summer creeps in, the buds begin producing flower clusters, AKA inflorescence, which will eventually bloom. The flowers, AKA perfect flowers, self-pollinate and do not require assistance from the bees. As the clusters develop, they produce tiny green berries in the process called fruit set. Good weather is the key to the flowering period, as too much rain can create issues possibly impacting the size and quality of the fruit at harvest time.
5. Veraison and ripening
During this stage, the most significant signs of life in the vineyard occur, and the shoots become mature ushering in the color changes of the green berries, AKA veraison, which takes place, and full ripening happens. As the green disappears gradually, each variety reveals its particular pigment. The white varietals take on a more yellow tint, and the red varieties go from green to black, purple, red, or blue. After veraison happens, acidity in the grapes remains high while sugar levels stay low, prompting some growers to do a pre-harvest of a few clusters right before the veraison stage begins, which removes some weight from the vines and concentrates energy on maturing those remaining grapes.
Finally, once the grapes are fully ripened, it’s time for harvest, which is done either by hand or machine, depending on the vineyard and preference of the winemaker. Harvests take place earlier or later depending on the specific conditions of that year’s growing season, and the challenges created by climate change are increasingly having a tremendous influence on timing as well.
Obviously, the grapes don’t ripen after being picked, but the vine’s leaves continue photosynthesis after harvest if warm temperatures are present. This is a crucial period for the plant, as it allows the accumulation of carbohydrates for future growth during next year’s cycle. As temperatures drop, the vines become increasingly accustomed to the cold and cause sugars to be converted to starch stored for the winter, mainly in the roots and trunks. After all the leaves have fallen, the vine continues to acclimate to the colder weather, the carbohydrate accumulation stops, and finally, the plant goes back into dormancy for the long winter months.
The beautiful process is a constant interaction between mother nature and human intervention where history and acquired knowledge get passed down from generation to generation and keep the traditions and methods alive!