Spring, an exciting time to be in the vineyards! After a long winter of dormancy, the vines get pruned severely in January and February in preparation to “bud break” in March and April. The vines go into a crazy rapid growth spree, often growing 1-2 inches a day.
Hidden under these ever growing leaves are generally 1-3 clusters per shoot known as “calyptras” or caps for short. These small green balls contain the pollen carrying parts of the flower. When the vines are ready, these “caps” burst to reveal the basic flower, a pistil and several pollen carrying stamen. The flowers on all grapevines are white and do not need the aid of bees for pollination, only a gentle wind that aids in the birth of the clusters
The grapevines start entering their flowering or “bloom” in May thru June depending on the location of the vineyard, elevation and most importantly, the weather. In a cooler rainier spring, their is a nerve-wracking period for vineyard owners that can either make, or break a vintage.
I interview winemakers weekly on my show oregonwine.tv and this being one of the top 5 rainiest Junes on record here in the Willamette Valley, it keeps these winemakers on edge as the vines are approaching full bloom. The 2 things you hope never happen at this time are heavy rain and hail, both can cause severe damage in the vineyard. When it rains, the fragile flowers and the pollinators can get knocked off which causes a condition called “shatter” whereas the grape clusters can form large and very small grapes within the same cluster, also known as “chicks” and “hens”. After the initial “set” of the grapevines, harvest takes place roughly 105-120 days later.
I hope you found this interesting, I find every aspect of wine grape growing FASCINATING..