Issue link: https://read.dmtmag.com/i/386317
A number of aging wine grape vineyards in Washing- ton State are entering or will soon be in the replanting phase of their lives. As growers choose new plant mate- rial, performance in the vineyard should be the top criterion, says the head of vineyards for Washington's largest grape grower and wine producer. "It's important you make careful, deliberate choices, because the decision will stick with you and impact your profi tability for forty-plus years," said Kevin Corliss, vice president of vineyards at Ste. Michelle Wine Estates. To ensure good performance in the vineyard, plant material must have superior fruiting capacity and quality traits, such as disease resistance, color, ripening, fl avors, and aromas. Corliss, who has more than 30 years of viticul- tural experience, recently shared the thought pro- cesses that he leads his Ste. Michelle colleagues through when choosing grape plant material for new vineyards or replants. Start clean Good vineyard performance starts with certi- fi ed, clean plants that have been tested for known viruses. "Clean plants are the first thing you should think about when planting a high perfor- mance vineyard," he said. "But you also need to know your vine source—where they come from— because the mother blocks will hold clues to their performance." At the very least, he recommends checking with the nursery about what the mother blocks look like, average yields the last ten years, when blocks were last sampled for viruses and which viruses. Plan A is to use certifi ed vines, but what often happens is Plan B, he said. When certifi ed vines are not available—as many were not in recent years because of rapid expansion of wine grape acreage throughout North America—growers should choose as close to second or next generation as possible and then perform extensive testing to determine the disease status of the block, he recommends. "We fi nd ourselves in this Plan B situation quite a bit," he said, adding that they test as many vines as practical, given constraints of time and money. One way to make testing easier is to keep the source block as small as possible. Also, learn as much as you can about the source block and keep detailed records in case you have to use the same source block for several years. "When it comes to using clean vines, you need to develop a long-term strategic vine-sourcing program," Corliss said. "You need to know what variety you'll be planting next and where to source that variety ten years from now. Someone within your organization should be tasked with that." Variety, clonal selections Planting a vineyard for good performance involves matching the variety with the site and style of wine, managing the vineyard properly, and selecting clones that bring complexity to the wine, while improving things like fruit- ing capacity, resistance to disease, color, or ripening, Corliss said. "Variety always comes fi rst." Too many people plant the wrong variety in their site, he said. For example, they want to grow long-season varieties, like Cab- ernet Sauvignon or Syrah, in cool parts of the state, where the mac- roclimate conditions just don't fi t the variety. Another reason he believes varieties have been planted in the wrong location is because Washington is still the "great frontier" of wine grapes, with vineyards planted in areas that were previously sagebrush. When selecting clones, which are asexually propagated vines and are the exact progeny of their parents, cleanliness is utmost important. "A clean, ho-hum clone is always better than a dirty but 'hot' one," Corliss said. He believes there is no perfect clone for Washington. Though there is no published research on wine grape clones grown in Washington State, Ste. Michelle has conducted its own clonal research trials since the 1990s and has years of clonal production and wine data. When selecting a clone, Corliss gives the following advice: 1. Study information from other areas. 14 OCTOBER 2014 GOOD FRUIT GROWER www.goodfruit.com Ste. Michelle Wine Estates will plant nematode-resistant rootstocks for the fi rst time in Washington on a small scale. by Melissa Hansen Some of the blocks at Canoe Ridge Estate, planted in 1991, are scheduled for replanting. As part of the replanting, Ste. Michelle Wine Estates will include a small rootstock trial. CHOOSE plant material WISELY "You also need to know your vine source … because the mother blocks will hold clues to their performance." —Kevin Corliss