When John was ready to plant his vineyard in 1982, he wanted the best Bordeaux varieties, specificially the clonal selections he found at Haut Brion.
Unfortunately none of these vines were available in California at the time. So he went to France and found a source for the Entav-Inra vines By 1999, John had started a nursery with licensed Entav-Inra vines and virgin ground to make these special clonal selections available to others.
In order to grasp the significance of what John did by propagating unique clones at Caldwell Vineyard, it helps to have some understanding of the difference between a variety and a clone.
A single wine grape variety like Chardonnay is created through sexual propagation, which is when the flower pollen (the male part of the flower) fertilizes the pistil (the female part of a flower) and creates a seed that grows up into a mature vine.
The challenge here is that every time you breed one grape variety with another, or even the same grape varieties together, you end up with a new, completely unique vine. Think of it like your parents and each of their offspring being different─no two brothers and sisters are exactly the same even though they share the same DNA.
Today we have 1,500 unique varieties that are the result of the germination of 1,500 seeds of the Vitis vinifera species. These modern varieties were developed over many centuries, as people selected for plants that created fruit with the most desirable qualities.
Lucie Morton, one of the most respected viticultural consultants and one of the only ampelographers (the identification and classifications of grapevines) in the U.S., explains it like this; “Once people decide they like a variety, then they take cuttings from the mother vine to create daughter vines that are 'clones' of that mother vine. This is known as vegetative propagation rather than sexual."
Over many years, those clonal daughters of one mother may develop subtle differences that are not a DNA change per se ... but rather changes in the quality of composition of a particular clone of a variety─for example, a slight change in the terpenes or phenolic components that make up flavor or aroma. These are selected for and propagated through clonal selection.
Growers select multiple clones within a given variety to achieve certain wine styles and also complexity. The buds from a clonal mother vine these days are almost always grafted onto a phylloxera-resistant rootstock. Propagation of these clonal selections is done at grapevine nurseries, just like John did at his own nursery in the mid 80’s with the certified Entav-Inra grapevine clones.
John wrote and published a professional reference book on clones with the help of research and translation of the original French papers by Philippe Melka. The book is called a Concise Guide to Grapevine Clones for Professionals. Get Your Digital Copy here.