Issue link: http://read.dmtmag.com/i/37334
A 2011 twin-leader planting of Minneiska (trade name SweeTango) on Mark rootstocks at Ray Fuller's organic orchard at Chelan, Washington, pictured in June. The two leaders were developed in the nursery on bench- grafted trees. An objective of the two-leader system is to fill the space quickly. Rootstock Fuller favors the Mark rootstock, which “Even if he says performs consistently well on his replant sites. He has a block, part on Mark rootstocks and the rest on Malling 9 337, that were planted as Gingergold 20 years ago and grafted over to Ambrosia about 10 years ago, with the two grafts forming a twin-leader system. The trees are 3 feet apart with 12 feet between rows. The trees on Mark filled their space, but those on Malling 9 never have. He used Mark for twin-leader plantings of SweeTango on 3- foot by 10-foot spacings in 2010 and 2011. Fuller is looking forward to using G.41 or G.4214 for the replant tolerance and disease resistance. On the newer plant- your cost per tree goes up, it’s not double.” —Ray Fuller ings, where the nursery trees came with twin lead- ers, Fuller expects the trees to reach the top wire by the second leaf. His goal is to harvest 50 bins by the fourth leaf. He estimates it will take a couple of years longer to reach full pro- duction on the trees that he had to cut back and regrow in the orchard. Once the trees reach the top wire of the trellis, Fuller cuts back the tops during the summer to maintain the height at 10.5 feet, just above the wire. Red Delicious Andrew Del Rosario, Tom Auvil (left) discusses a new Washington Fruit and Produce Company planting on Washington's Royal Slope with orchard manager Mike Roskamp, horticulturist Andrew Del Rosario, and foreman Neftali Pereira. The Red Delicious trees, on Malling 106 rootstocks, will be trained as twin-leaders in an effort to establish the block quickly. Two similar-sized shoots—not necessarily the top two—would be selected as the leaders. should result in a tall, thin, uniform canopy that opens up possibilities for mechanizing some orchard practices in the future, such as pruning and thinning. “In this production system, we’re not looking for any branches—it’s all bourse shoots and spurs less than one foot long,” he said. Auvil recommends supporting the tops of the leaders with kite string (often sold as pea string) or bamboo and removing fruit at the top of the trees to encourage them to grow up to the top trellis wire. “The longer an unsupported leader is flopping in the wind, the more vigor loss will occur,” he said. In Fuller’s experience, the two leaders rarely grow equally at first in the orchard, but he said he’s not too concerned because the variability lessens as the plantings mature. Auvil said one way to even out the growth is to tilt the most vigorous of the leaders at a slight angle, which will slow it down, while making sure that the less vigorous one is growing vertically. www.goodfruit.com horticulturist with Wash- ington Fruit and Produce Company, also experi- mented with twin leaders in a block of Fuji planted on M.9 rootstocks in 2008. The trees are four feet apart with ten feet between rows, and the two leaders were developed in the orchard from bench- grafted trees. He’s maintained some strong branches in the lower parts of the tree as “cheaters” to gain early production while the trees are growing, he said. As the trees grow, the larger wood will be shortened or removed to create a two-foot-wide canopy. In trees where one of the leaders has grown poorly, he’s removed the weakest leader to focus on developing the remaining one and filling the tree space. Washington Fruit is also training a 2011 planting of Red Delicious on M.106 rootstocks to a twin-leader system with the goal of establishing the orchard more quickly. The trees were planted four feet apart with ten feet between rows. They were headed back at plant- ing, and as the trees began to grow, two similar-sized shoots were selected as the future leaders and supported with string attached to the trellis. Auvil said the challenge with Red Delicious is to get the trees to grow tall, and any cropping will delay the vertical growth. The planting is on a four-wire trellis, and Auvil indicated the trees should grow five inches per week with a goal of 50-plus inches of vertical growth by the end of the first growing season. • GOOD FRUIT GROWER AUGUST 2011 43 GERALDINE WARNER GERALDINE WARNER GERALDINE WARNER