Orchardist Greg Johnson, with experience from several different tree training systems, is moving all of his cherry blocks into more pedestrian-style orchards.
Johnson, a cherry grower from The Dalles, Oregon, has been on a replanting quest for more than ten years, updating the orchard that he bought from his grandparents. He shared his experiences with the Spanish bush, KG (Kym Green) bush, and central leader training systems during recent cherry grower talks in Yakima, Washington.
“Most of the orchards were old, planted in the 1960s—and that was the young stuff,” he said in describing Renken Orchards. “I wanted a pedestrian orchard with ease of pruning and picking.”
Along the way of experimenting with the three different systems, he’s learned the pros and cons of each. He noted that he has never been to Australia to visit Kym Green, who developed the KG bush, or to Europe to see firsthand the Spanish bush system.
Johnson first tried the Spanish bush, planting Royal Ann cherries to Gisela 7. The block is “truly” a pedestrian orchard—ladders are not used and picking is very efficient, he noted. But the training system is harder to prune than the KG bush, and requires an “art” to pruning. He is concerned with renewal wood, shading, and frost, an issue that can plague short trees.
His first experience with the KG bush system was in a Sweetheart on Mazzard block, spaced at 8 feet by 15 feet. The block started out as a Spanish bush system, but he converted it to the KG bush. Johnson acknowledged that the tree spacing is tight, but he is hoping that the tightness will encourage renewal branching.
“Large wood is a problem if the tree isn’t started correctly,” he said, adding that the block still looks somewhat like a Spanish bush and has big wood in the trees. He wants to achieve branches that are the diameter of his thumb.
A newer KG bush block of his is doing better, he said, and has more uniform trees and more uniform growing points with similar diameter.
Advantages of the KG bush are several, including ease of pruning, ease of teaching workers what to prune, and little use of ladders needed. Trees are pruned after harvest, with tree height set by pruning at the end of fall. In the spring, workers concentrate on pruning to provide renewal wood.
Mildew can be a problem in the KG bush, especially with some varieties, he noted. “Lapins and Sweethearts can be vacuums for mildew and really suck it in if you’re not careful.”
The KG bush has less structural wood than the Spanish bush, which is a more permanent system and can have shading issues, Johnson said. “With the KG bush, everything is renewal wood.”
Many of his blocks are on Mazzard rootstock and trained to the central leader. With the central leader, he has to work to keep vigor on the bottom of the tree. “Mazzard wants to blow everything out at the top.”
He found that Chelan and Sweetheart work well on Mazzard, and he has Lapins on Gisela 6 trained to the central leader.
Strengths of the central leader are tree uniformity and ease of pruning. However, the orchards are not completely pedestrian, requiring ladders for about 25 percent of the orchard tasks. He is concerned about sunburn potential, particularly in Lapins.
While he’s still growing Rainier cherries on the central leader, he is taking out most of his other central leader blocks. Though he likes the central leader, he’s found that worker productivity is much higher in the KG bush blocks because the trees are easy to pick and prune without ladders.