How climate affects wine grapes, or what do you mean I can’t grow my own Cabernet?

We were recently talking about Florida wineries, and the question came up: why don’t more Florida wineries make “real” (i.e. California-style from familiar grapes) wine? Short answer: Florida’s great weather isn’t so great for growing (wine) grapes.

To understand how climate affects grapes, you first need to know there are three general groups of grapes.

American grapes (Vitis lambrusca), which are the most cold-hardy grapes, and which grow in the northeastern United States.  (Catawba, Delaware, Niagara)

European grapes (Vitis vinifera), which grow best in sunny climates with warm summers and mild winters, such as California.  They are cultivated on every continent on Earth except for Antarctica.  (Cabernet Sauvignon, Merlot, Syrah etc.)

Muscadine grapes (Vitis rotundifolia), which are native vigorous vines that adapt well to heat and humidity.  (muscadines, scuppernong)

Muscadine variety

Knowing what species of grapes grow best in specific areas makes it possible to grow grapes almost anywhere, if not exactly what you want, exactly where you live.

Keeping this is mind, you’ll notice that vinifera grapevines prefer temperate climates with warm, dry summers and mild winters.  A winter of sustained cold kills grapevines. High humidity promotes vine disease. Tropical temperatures disrupt the normal vine cycle of winter dormancy. Without a period of dormancy, grapes tend to ripen unevenly from one bunch to another, and even within a bunch. (Pruning is done when the vines are in this dormant stage).

In Brazil, they deal with the lack of winter by pruning the vines and stripping off all the leaves once a year.  This simulates a dormant period and gets the fruit ripe at the same time.

Dormant vineyard
Dormant grapes

The question arises as to whether you can grow grapes in subtropical climates. Specific varieties were developed to suit the Florida climate, such as Stover, Blanc Du Bois, Swanee and Miss Blanc. The muscadine grape from the Vitis rotundifolia  species is a Florida native and does well in the hot, humid climate, but the European varieties (Vitis vinifera), such as Merlot, Cabernet Sauvignon and numerous others, do not do well.  The tropical weather makes them susceptible to a wide range of diseases.

To be continued….

Marie Griffin, West/Northwest Florida Wine Supervisor

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