BUD BREAK IN GRAPE VINES AND VINEYARDS
For the vine-grower, bud break represents the beginning of about seven months of work before harvest, during which the vine must be protected from pests, vine diseases, and trained as necessary. The biggest problem for many vineyards at this time of the year is spring frost, to which the young shoot growth is particularly sensitive.
Bud break, budburst, or budding, describes the yearly stage in which buds open giving rise to the seasonal sprouts. It is preceded by bleeding of the cuts performed during pruning and normally takes place in the early spring, though it is highly influenced by temperature variations.
Due to the natural physiology of the vine as a climbing plant, bud break is accentuated in buds which are further away from the trunk and hence the importance of pruning and its timing (late pruning delays bud break). It should also be taken into account that under similar conditions, neither do all grape varieties bud at the same time nor do they react in the same way to temperature variations.
For vines which are properly pruned (balanced pruning) most of the buds left at winter pruning will brust. However, bud break is normally lower for buds in the middle of long canes. When vines are left unpruned, as in minimal pruning, it is the buds near the ends of canes which burst preferentially, as do higher buds. This adaptive physiology helped vines to climb trees and seek sunlight in their evolutionary forest habitat.
The two buds on either side of the cane just below the pruning cut typically burst. This is because of the flow of hormones in the plant and is the reason for pruning to two bud spurs. Spur is the part of the shoot which is left after pruning, more o less of the length of a thumb (from where the Spanish name of "pulgar" derives), generally with two buds (thought they may gold up to four). It is the one which will generate the cane bearing the fruit the next year.
Spur pruning is the most aggressive that may be carried out on the vine stock for it eliminates up to 90% of the previous year´s growth. In cane pruning (longer shoots) spurs are also left which will be the replacement canes in the next season.
Pictures of Urbina Winery Vineyards in Cuzcurrita del Río Tirón D.O.Ca La Rioja. Produced only with grapes from their own vineyards, making a respectful viticulture, with organic fertilizers, maintaining the richness and structure of the soil, contributing to the fruit and the essence that characterizes Urbina wines.
