5 Wine Pruning Facts

Crisp breezes freshen the air. Sunlight caresses grapes, making them glow. Plump with juice, the generous bunches pull toward earth. It's going to be a glorious harvest.

Ah, if it were only so easy. Before you drink the wine, you have to grow the vine, and annual pruning is an essential step to enjoying healthy, flavorful grapes at fall harvest.

"The first year we pruned, we were very nervous," said Doug Paul. He and his wife, Sharon, own and operate Three Sisters Vineyard and Winery in the north Georgia mountains. "Most beginning wine growers don't prune enough."

Pruning means cutting off canes, or branches, that could produce grapes. Giving up part of your crop is a hard thing for any gardener to do, but if you don't prune, the vines produce more grapes than they can fully support. By removing excess canes, you let the plant concentrate its energy in the selected canes, which ensures the grapes that are allowed to grow reach their optimal size and flavor. Removing damaged or diseased plant parts is another important function of pruning.

Next up, learn when to prune your vines.

Pruning has two phases: winter vine thinning and summer foliage trimming. With winter pruning, your goals are to eliminate crowding, select growth points for this year's crop and set the stage for next year's crop. Late winter to early spring is the best time for vine pruning -- when the worst winter weather is behind you but before spring blooms appear. At Three Sisters Vineyard, pruning begins in December and wraps up by early March.

"Grapes store energy in their root balls," Paul said. "You don't want to drain off energy too early."

Vines pruned too early are also more susceptible to fungal disease. Fall rains splash fungal spores up from the ground onto the plant, where fresh pruning cuts are susceptible to infection. Summer pruning involves hedge trimming the leaves.

"During the summer growing season, leaves provide shade around the fruit, but within the last month before harvest, you want to remove some foliage," Paul explained. "You also want to keep the vines off the ground."

Most wine grapevines are grafted onto disease-resistant root stock. If vines touch the ground and begin to root, they lose the benefit of the hardier root stock and become vulnerable to disease.

See how much to prune on the next page.

Your dormant vine may look like a dense tangle. After pruning, it'll look lean and orderly. "Pruning is a part of the control of the vine," said Paul. "You don't want the vine to take over."

On mature vines, the number of buds to keep depends on how much the pruned canes (branches) weigh. If you prune one pound (0.5 kilogram) of canes from a vigorously-growing varietal, you can leave 30 growing nodes -- budding points in joint-like rings along the canes -- on the vine. On slower-growing varietals, limit the vine to 20 nodes. For every additional pound (0.5 kilogram) of pruned canes, add 10 nodes.

Pruning is also important for disease control. By removing injured or infected plant parts, you encourage new growth and mitigate the spread of disease. Once growth begins, a properly pruned vine is open to sunshine and air flow. These healthy-growth essentials encourage vigor in the vine by facilitating photosynthesis and deterring many diseases and pests.

In general, vines of American grapes grow in flowing curtains that weep downward like a willow tree, and French grapevines grow more upright, like tomato vines. For all vines, new growth originates from shoots. Shoots grow from nodes (the areas of buds along the branches of the vines). Canes are branches that grew the previous year from a one-node spur on the cordon, the horizontal arms of the vine.

When you prune, you want to keep evenly spaced canes for growing the current year's crop, and about twice as many spurs to grow canes for next year's crop. French varietals are pruned to remove all growth points that aren't on the top of the cane. Because American vines grow downward, growth points are allowed to emanate from the top, sides and bottom of the horizontal cordon.

To begin winter pruning:

You can't prune vines without the proper tools, so read on to the next page to learn about them.

Pruning tools are very simple: You need a pair of sharp, heavy-duty pruning shears -- secateurs if you want to impress friends with your French. While there is vine pruning machinery, it's generally considered pre-pruning equipment. Driving between rows, it embraces vines with two side blades and a top blade, chopping canes as it goes. To get a satisfactory crop, you'll need to do a second pruning by hand.

"You really need to spend time with the vines," said Paul, who also pointed out that the hilly terrain of many vineyards isn't suitable for pruning machinery.

Keep your pruning blades sharp, clean and lubricated to reduce injury to vines. Some growers dip blades in a solution of one part bleach to nine parts water between cuts to prevent spreading disease. You can also wipe the blades with rubbing alcohol.

Grapevines are long-lived perennials, and with proper pruning and care, they can thrive for decades.

Learn much more about wines and winemaking on the next page.