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w w w. v w m m e d i a . c o m N o v - D e c 2 016 | V I N E YA R D & W I N E RY M A N A G E M E N T 4 7 done on this subject doesn't sug- gest a significant problem. Larger vineyards have to start in late fall in order to complete dormant pruning before bud break." Most experts say the later a vineyard is pruned, the better. When logistically possible, Wolf recommends waiting until late win- ter to permit proper assessment of potential damage. "Once the wood is removed, there's little or no room for compensation if you have a subsequent low temperature epi- sode that injures buds or wood," he says. "This ability to compen- sate for cold injury by leaving more buds or extra canes is the principal reason for delaying pruning as long as possible." His secondary reason for delay is that waiting for warm- er weather can potentially reduce infections by wood-rotting, fungal pathogens — such as Eutypa and Botryosphaeria — that are active during rainy, cool weather. In Northern California and other mild climates where winter dam- age rarely occurs, pruning prefer- ably happens at the same time, but the motivations are a bit different. "The primary motivation [for late pruning] is disease prevention, but for early budding varieties like Pinot Noir and Chardonnay, you get frost protection benefits as well," says Kristin Lowe, Ph.D., owner of Vine Balance Consulting in Napa, Calif. "[Growers] like to make their cuts in the later winter or early spring when the weather is warmer and dry to prevent disease infection. Most people know to follow the weather," says Lowe. Even though experts agree on timing, complications arise when factoring in vineyard size, labor availability and favorable weather. One or more of these issues may demand an earlier schedule, so a grower might use double prun- ing to counter possible impacts. "Double pruning means an initial pruning cut is made five inches or more beyond the desired point of the true cut during winter pruning," says Wolf. Or, in the case of cane pruning, several extra canes are left as back-ups should the originals be damaged. Instead of making one More and more growers across the nation recognize the multifac- eted protection afforded by double pruning. "In Michigan, the spring frost is becoming an issue due to climate change, and we're plant- ing [hybrids] that tend to have very early bud break," says Paolo Sab- batini, associate professor of horti- culture at Michigan State University in East Lansing, Mich. "The clas- sic example is Marquette. People say this is impossible, you can't kill Marquette. But if you get two or three spring frosts in a row, you can kill a vine. So the double pruning technique is something we'll see more of in the future." Sabbatini also explains that, due to the cold winters and wide array of varieties planted in Michigan, grow- ers there typically schedule pruning according to the physiology of each variety. "We start by pruning the very hardy first, then hybrids, leav- ing vinifera for last," he says. round of cuts, pruning is split into two, quicker sessions. In frost-prone sites, you can avoid frost damage by encourag- ing your count buds to push later, after the risk of frost has passed. You accomplish this by double pruning. This involves running a pre-pruner through your vineyard at a height that leaves a couple internodes above what you'd leave when you come in and hand prune. "You'd typically come through with a pre-pruner to reduce the amount of wood anyway," says Richard Hoff, director of viticul- ture at Mercer Canyons in Prosser, Wash. "For your cooler sites, with early bud-breaking varieties like Chardonnay, you can come back through and prune again to get the lower buds to push later, once the most apical buds have already pushed." Hoff has mechanized the majority of Mercer Canyon's prun- ing operations, but the value of double pruning applies to all prun- ing methods. "I'm giving myself a bit of an insurance policy with the amount of buds I'm leaving during pre-pruning. I feel I can start earlier because, even with a major winter freeze event, I have 100% more buds than I want." Richard Hoff of Mercer Canyons in Prosser, Wash., advises double pruning frost-prone sites. Toll-Free: 877-552-4828 909-464-1373 • Fax: 909-464-1603 For your nearest dealer, contact: GREENTIE™ GreenTie™ is a UV stabilized tie that is easy to tie and re-tie. Ties are available in 11-1/2" length and are an economical choice for agricultural fastening. V&WM GreenTie Ad.qxp_Layout 1 12/2/14 11:08 AM