Should you graft or replant?

An example of a field-grafted vine.

Reasons to redevelop a vineyard vary—the vines may be the wrong variety, riddled with disease, or no longer productive. But when it’s time for a change, do you graft or replant?

Many of the juice grape vineyards in Washington State were planted in the 1960s; older wine grape plantings are nearing 50 years old. Washington’s Concord industry is an aging industry, and the wine grape industry is heading that way, too, said Mike Concienne, area manager of National Grape Cooperative Association (Welch’s). “For a lot of vineyards, the question is, are they productive and economical enough that they should still be in ground?” he asked.

Concienne said that as grape growers begin contemplating vineyard redevelopment, they want to know if they can replant in the same vineyard, and will the new planting be successful.

A trio of grape growers and a soil scientist shared their vineyard redevelopment experiences during a panel discussion at the annual meeting of the Washington State Grape Society. Though most think of replanting or grafting when a vineyard needs redevelopment, replacing vines as old ones give out can be a way to keep the ­vineyard productive.

Washington’s largest wine company Ste. Michelle Wine Estates has had limited experience in replanting vineyards. But Kevin Corliss, vice president of vineyards, believes that a combination of factors will increase the need to replant in the near future. Diseases like grapevine leafroll virus are becoming more prevalent and affecting the grape quality in Washington, and vineyards in the state are getting older.

In the instances where Ste. Michelle has replanted, Corliss said that the reasons were usually market driven. “More often than not, the variety falls out of favor,” he said. “The life of a vineyard really depends on the market. That’s usually the reason why we consider replanting a vineyard.”

Grafting

Ste. Michelle has used three strategies to redevelop a vineyard: grafting, replanting under the existing trellis and irrigation systems, and what Corliss calls the “full meal deal” of starting over.

Grafting has been done when varieties need to be changed; however, he’s not a big fan of the technique. With a success rate of about 65 percent take on the first grafting pass, he said their results have been marginal, though others have had better results.

Even several years later, after regrafting the first unsuccessfully grafted vines, he said the grafted vineyard only looks okay, not great. “Those vines that we’ve had a time getting going just always seem to struggle.”

Corliss believes there is room for learning to improve the grafting take, because grafting has a big cost advantage over replanting. Grafting costs about 75 percent less than putting in a new planting. However, he cautions that some winemakers believe that fruit quality is less from a grafted vine than fruit from own-rooted vines.

Replanting

Ste. Michelle has replanted within the existing vineyard structure when the spacing, and trellis and irrigation systems are suitable for the new planting. But they have experienced “replant syndrome” in some instances—some vineyards did just fine when vines were ripped out in the winter and replanted the next spring, but others have not done well, and are still not doing well.

“We don’t really know what’s going on, but our brothers in the apple industry and other perennial crops have had replant issues,” Corliss said. The inconsistent replant results led him to fumigation, and his standard practice now is to run metam sodium through the drip irrigation system after harvest over the vines that are to come out. After sitting through winter, the vines are cut off at ground level, yanked out of the ground, and replanted the ­following spring.

Thus far, he’s had good results in killing the vines (killing about 95 percent) and the vines generally are easier to remove. Soil samples show very low numbers of nematodes after the soil fumigation.

In a 30-year-old Semillon block that was replanted this way to Chardonnay, he reports they’ve had good growth and vigor.

“It’s an ugly, tediously slow, and hideous process,” he said, adding that vine removal often damages the trellis and irrigation systems. “The older the vineyard, generally the more repair that’s needed,” he said. “But you have a fresh slate to plant into.”

Some contend it would be easier to remove trellis and irrigation lines and just start over, but Corliss points out that this replanting strategy of leaving the infrastructure in place, is about 50 to 70 percent the cost of a new vineyard, depending on how much of the existing infrastructure can be utilized. He believes it has merit for growers producing grapes in a lower tier wine style because of the economics.

The “full meal deal” is used when the trellis, spacing, or irrigation are no longer wanted (wooden poles and stakes, wide vine spacing). “The full meal deal is our ­preferred strategy and we do it when the vineyard is located in valuable real estate,” he said, noting that it’s done in vineyards producing high-tier fruit.

The full meal deal starts with open ground (existing trellis and irrigation systems are removed). The field is then ripped, fertilized, soil amendments added, and new trellis and irrigation systems installed. Cost of a vineyard planted in this manner is 110 to 120 percent the cost of starting a new vineyard, due to the remediation costs associated with taking the field back to “bare ground.”