The Inventive Grapevine

By Posted on Feb 04 2010 | By

Freeloader. Hardly a term we think of when the grapevine comes to mind.

Sadly, it’s true. All those beautiful vineyards that inspire poets and artists and provide us the nectar of the gods are populated with a bunch of selfish little wannabes. It’s fortunate we’ve learned how to control the rascals.

The grapevine has evolved over time to take advantage of others. And we in turn have learned how to take advantage of it. What goes around comes around.

A vine really has only two desires in life: earth and sky. Long ago the vine looked around and was amazed how much time trees waste in growing huge trunks to support its life-giving canopy. Trees devote decades to bulking up so they can tower over other vegetative growth and bask in the life-giving rays of the sun. The grapevine ruminated on this waste of energy and thought, “I’ve got a better idea.”

And indeed it did. Rather than devote hard-earned resources in assembling a mechanical structure to touch the sky, the vine employed a quick and easy route to nirvana; climb on the backs of trees and race to the sun in record time.

Once the vine chose to pursue this survival strategy, it simply got better at it as time went by, perfecting its behavior over a 130 million year stretch. When the English colonists landed in Jamestown, they were astonished to encounter virgin forests draped with wild vines and grapes. Such heavy growth could even threaten the well being of the host tree. Although, it wouldn’t have been too smart to snap a trunk and end up lying on the forest floor looking for another victim to climb upon.

Kudzu Vines

An egregious example of a non-grape vine taking advantage of its host is the Kudzu vine. Originating in Japan, it was introduced in the United States in 1876 as a forage crop. Starting around 1935, it was given a new lease on life as a soil erosion agent. Over time, it rejoiced in the hot, humid summers of our southeastern states and the rest is history. The vine’s population exploded and today wide swaths of forests can be seen draped in green blankets of vines. Voodoo Kudzu.

The Greeks were the first culture to abandon the practice of allowing vines to do their tree climbing tricks. Instead, they developed a system of training vines to grow on trellises and stakes, a technique eventually adopted by all grape growers. It was at this point in history that man began to manipulate the vine and use its natural growing traits to advantage. It also was a bit safer than scampering up tall trees to harvest their wine.

Once the vine was placed in the harness of a trellis system, its urge to grow profusely needed manipulation. A variety of trellis and pruning techniques emerged to increase the quality and flavor of the grape crop. If vines aren’t shown “tough love”, they will grow profusely, the canopy overflowing and hiding the fruit and introducing the opportunity for fungus and mildew attacks. Vine growers have been managing these challenges for centuries and today’s vineyard managers are still vigilant in protecting and treating their disease-prone vines.

The stages of grape development begin after harvest when the vines fall into a winter dormant stage to protect themselves from the harsh climate. As solar energy increases in spring, the buds begin to swell, then break open with associated leaf unfolding and flowering, followed by fruit set and the formation of berry bunches, later to evolve into the iconic grape clusters.

As this stage of development progresses, the grape’s wildlife enemies slowly become aware that the vine is not growing up trees but offering easy pickings on low hanging trellises. Commercial vineyards protect their crop with nine-foot high fences to thwart deer and bear predation. The vine’s natural ability to grow away from such threats has been compromised by man’s intervention to keep it relatively close to the ground. Nonetheless, its ancient defensive mechanisms still provide some protection. The vine camouflages its grapes the same color as its leaf canopy and maintains high acid levels to make the fruit unappetizing to animals and birds. Not until the grapes near maturity will it drop its guard and let the fruit become more attractive to depredation.

After the threat of killing spring frosts, one of the most vulnerable times for wine growers occurs in late summer when the fruit begins to undergo veraison, or the changing of color. During this phase, grape sugars begin to increase and natural acids start receding. The vine has no clue that man has been working all year long to reach this important stage. This phenomenon is essentially a public announcement to wildlife to move in and have a bite of the tasty ripening fruit.

The green fruit turns either a translucent golden color for white grapes or a purple-black for red grapes. In both cases, it’s a visual signal for our feathered friends and other wildlife to begin picnicking. The vine’s purpose for the color change is to lure the animal kingdom into eating, and then disseminating, digested grapes seeds over a wide area. It’s a pure and simple survival mechanism designed to propagate the species.

And it’s exactly what wine growers don’t want to happen. The vine’s natural impulse is to take advantage of hungry critter appetites for propagation purposes. But its urges must again be reigned in. During the months of August and September, you will often see vineyards swathed in diaphanous netting to block the dance of the vine and the fowl.

In addition to bird visitations, deer and bear focused on beefing up for the winter months cannot resist gormandizing on the fruit. A sow bear and her cubs roaming freely in a vineyard can wipe out a season’s worth of work in a few nights. Maintaining bear and deer proof fencing is high on a vineyard manager’s to-do list during this part of the growing season. Although, it’s mighty hard to stop a determined bear unless you unleash the hounds.

As harvest draws to close, the vines—sans their leaves—are allowed to acclimate to winter temperatures for a few months before pruning begins. If pruning intervention did not occur, spring would see an explosion of foliage as the vines drop to the ground and seek adjacent trellises. Picture the rampaging Kudzu vine. Left unpruned, grapevines would slowly spread across a vineyard smothering as much territory as possible.

So has man always been destined to control and reap the bounty of the grapevine? Perhaps. Even Genesis 1:26 states, “And God said…Let them make dominion over every creeping thing that creepth upon the earth.” And so it is.

Published in the February 4, 2009 edition of the Culpeper Times.

Categories : WINE ARTICLES