Ampelography 101: A Test in the Vineyard

We have been walking the field to see which plants need replacement. What this entails is a close look at all 6800 of our vines. I love this part of vineyard work. Now that they have been budding out and really showing their leaves, we find that it is very interesting. The new leaves on our Auxerrois has a red tinge. In my head, I say in my best Anne Burrell voice "Hi, cutie!" (Okay, I'm watching too many episodes of Food Network and I know that is going to change soon.)
Walking the field is a lesson in ampelography, which is the field of botany concerned with the identification and classification of grapevines traditionally done by comparing the shape and colour of the vine leaves and grape berries.¹ We first encountered ampelography when we visited Mercier, CA and Sebastian took us on a tour of the mother blocks. He showed us how the leaves of the different varieties of grapes differ and this is one way of telling them apart.

We now have two books on ampelography. One is a 1979, translation and adaptation of Pierre Galet's book, A Practical Ampelography, Grapevine Identification by Lucie Morton. The other is an updated compilation by Pierre Galet entitled Grape Varieties. As we walked the field, we also saw plants that had both the scion growing as well as our rootstock, as shown on the photo on the right. Since our vines are tall grafted vines, it is really easy to distinguish any growth coming from our rootstock, which is 101-14 MGT. (More on rootstocks in another blog.) Now for the test:

A few moments later, we came upon the vine that had foliage resembling what we had identified as our rootstock, 101-14 MGT. When we looked closer, it was the rootstock. On the right side in the photo above is the vine that sprouted rootstock because the scion had become dislodged. Close observation and attention in the vineyard is paying off.
References
1. Definition of Ampelography on Wikipedia.